Kill LED lamp flicker...

M

Mike Monett VE3BTI

Guest
I recently changed the overhead fluorescent lamps for LED replacements.

Very soon, I noticed they were flickering a lot more the the old
fluorescents.

They flicker on the slightest line disturbance, from someone turning on a
microwave to who knows what outside the building. It turns out the
bandwidth of LEDs is much higher than gas lamps. Good to know if you\'re in
the spying business, but not good in the shop.

I studied various methods of supplying clean power, from LifePO4 batteries
to my own solar array. Very expensive, and can\'t avoid batteries.

I settled on a brute force attack, using a dimmer and huge capacitors. The
dimmer is needed as a PWM to reduce the rectified line voltage from 160
volts down to 125 volts. The dimmer also allows to dim the LEDs to arrive
at a more comfortable illumination. They are very bright.

The lED lamps contain their own bridge rectifier to convert the AC line
voltage to DC to drive the lamps.

There is one trick in the circuit that is of note, and is why I am posting
the circuit here.

It is necessary to break the dimmer AC line between the delay pot and the
triac to insert a 10 ohm resistor. The resistor cuts down on the surge
current during startup, but it causes a drop in line voltage. If this drop
is applied to the delay pot, the circuit goes haywire during startup.

Note the 1N4007 diodes are replaced by a regular bridge rectifier with
suitable ratings. It is easier to model using 1N4007s than trying to find a
bridge rectifier in LTspice.

The circuit has been tested on LTspice IV and XII. I will never run QSpice
since is requires MS 10-11 and 64 bits. I got off the Microsoft merry-go-
round at Win7, and I am perfectly content to stay there.

From past experience it may be necessary to fiddle with the Model
statements to get the program to load in LTspice. The line wrap in the
newsgroup creates havoc on LTspice.

Here\'s the ASC file:

Version 4
SHEET 1 1684 680
WIRE 176 16 -16 16
WIRE 224 16 176 16
WIRE 368 16 304 16
WIRE 432 16 368 16
WIRE 480 16 432 16
WIRE 592 16 544 16
WIRE 368 32 368 16
WIRE 176 64 176 16
WIRE -16 112 -16 16
WIRE 368 128 368 112
WIRE 464 128 368 128
WIRE 480 128 464 128
WIRE 592 128 592 16
WIRE 592 128 544 128
WIRE 624 128 592 128
WIRE 640 128 624 128
WIRE 656 128 640 128
WIRE 752 128 736 128
WIRE 864 128 752 128
WIRE 368 144 368 128
WIRE 640 160 640 128
WIRE 864 160 864 128
WIRE 752 176 752 128
WIRE 176 208 176 144
WIRE 224 208 176 208
WIRE 256 208 224 208
WIRE 176 224 176 208
WIRE 432 272 432 16
WIRE 480 272 432 272
WIRE 592 272 544 272
WIRE 640 272 640 240
WIRE 640 272 592 272
WIRE 720 272 640 272
WIRE 752 272 752 240
WIRE 752 272 720 272
WIRE 864 272 864 240
WIRE 864 272 752 272
WIRE -16 304 -16 192
WIRE 176 304 176 288
WIRE 176 304 -16 304
WIRE 368 304 368 208
WIRE 368 304 176 304
WIRE -16 320 -16 304
WIRE 464 352 464 128
WIRE 480 352 464 352
WIRE 592 352 592 272
WIRE 592 352 544 352
FLAG -16 320 0
FLAG 368 16 A
FLAG 224 208 VC1
FLAG 752 128 C
FLAG 720 272 D
FLAG 368 128 B
FLAG 624 128 E
SYMBOL misc\\\\DIAC 320 176 R90
WINDOW 0 0 32 VBottom 2
WINDOW 3 64 32 VTop 2
WINDOW 123 92 32 VTop 2
SYMATTR InstName Q1
SYMATTR Value2 VK=30
SYMBOL voltage -16 96 R0
WINDOW 0 10 -1 Left 2
WINDOW 3 -65 137 Left 2
WINDOW 123 0 0 Left 2
WINDOW 39 0 0 Left 2
SYMATTR InstName V1
SYMATTR Value SINE(0 166 60 0 0 0 20)
SYMBOL res 160 160 M180
WINDOW 0 36 76 Left 2
WINDOW 3 36 40 Left 2
SYMATTR InstName R1
SYMATTR Value 200k
SYMBOL cap 160 224 R0
SYMATTR InstName C1
SYMATTR Value .062u
SYMBOL misc\\\\TRIAC 336 144 R0
SYMATTR InstName U1
SYMBOL diode 544 0 R90
WINDOW 0 0 32 VBottom 2
WINDOW 3 32 32 VTop 2
SYMATTR InstName D1
SYMATTR Value 1N4007
SYMBOL diode 544 112 R90
WINDOW 0 0 32 VBottom 2
WINDOW 3 32 32 VTop 2
SYMATTR InstName D2
SYMATTR Value 1N4007
SYMBOL diode 480 288 R270
WINDOW 0 32 32 VTop 2
WINDOW 3 0 32 VBottom 2
SYMATTR InstName D3
SYMATTR Value 1N4007
SYMBOL diode 480 368 R270
WINDOW 0 32 32 VTop 2
WINDOW 3 0 32 VBottom 2
SYMATTR InstName D4
SYMATTR Value 1N4007
SYMBOL res 624 144 R0
SYMATTR InstName R2
SYMATTR Value 230
SYMBOL cap 736 176 R0
SYMATTR InstName C2
SYMATTR Value 1640uf
SYMBOL res 752 112 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R3
SYMATTR Value 0.1
SYMBOL res 352 16 R0
SYMATTR InstName R4
SYMATTR Value 1k
SYMBOL res 320 0 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R5
SYMATTR Value 10
SYMBOL res 848 144 R0
SYMATTR InstName R6
SYMATTR Value 100k
TEXT 40 -48 Left 2 !.tran 0 500ms 0 10u
TEXT -376 280 Left 2 !.subckt DIAC T1 T2\\n* default parameters\\n.param RS=
10 ; series resistance\\n.param VK=20 ; breakdown voltage\\nQ1 N002 N001 T2 0
PN\\nQ2 N001 N002 N005 0 NP\\nR1 N002 N004 {20K*(VK-1)}\\nR2 N004 T2 9.5K\\nR3
N002 N005 9.5K\\nQ3 N004 N003 N005 0 PN\\nQ4 N003 N004 T2 0 NP\\nR4 T1 N005
{RS}\\n.model PN NPN Cjc=10p Cje=10p\\n.model NP PNP Cjc=10p Cje=10p\\n.ends
DIAC
TEXT -376 16 Left 2 !.subckt TRIAC MT2 G MT1\\n.param R=10K\\nQ1 N001 G MT1 0
NP\\nQ2 N001 N002 MT2 0 NP\\nQ3 N002 N001 MT1 0 PN\\nQ4 G N001 MT2 0 PN\\nR1
MT2 N002 {R}\\nR2 G MT1 {R}\\n.model PN NPN Cjc=10p Cje=10p\\n.model NP PNP
Cjc=10p Cje=10p\\n.ends TRIAC
TEXT 40 -80 Left 2 ;\'DIAC TRIAC Light Dimmer Step RDim
TEXT 64 336 Left 2 ;200e3*.062e-6 = 0.0124 seconds
TEXT -56 432 Left 2 !.model 1N4007 D(Is=14.11n N=1.984 Rs=33.89m Ikf=94.81
Xti=3 Eg=1.11 Cjo=25.89p \\n+M=.44 Vj=.3245 Fc=.5 Bv=1500 Ibv=10u Tt=5.7u
Iave=1A Vpk=1500 mfg=Motorola type=silicon)
TEXT 632 312 Left 2 ;100e3*1540e-6= 154 seconds

The PLT file

[Transient Analysis]
{
Npanes: 2
Active Pane: 1
{
traces: 3 {524293,0,\"V(d,c)\"} {524294,0,\"V(d,e)\"} {34603012,1,\"I
(R3)\"}
X: (\'m\',0,0,0.05,0.5)
Y[0]: (\' \',0,0,10,130)
Y[1]: (\' \',0,-4,2,22)
Volts: (\' \',0,0,0,0,10,130)
Amps: (\' \',0,0,0,-4,2,22)
Log: 0 0 0
GridStyle: 1
},
{
traces: 2 {524291,0,\"V(b)\"} {524290,0,\"V(a)\"}
X: (\'m\',0,0,0.05,0.5)
Y[0]: (\' \',0,-180,30,180)
Y[1]: (\' \',0,1e+308,3,-1e+308)
Volts: (\' \',0,0,0,-180,30,180)
Log: 0 0 0
GridStyle: 1
}
}


--
MRM
 
On 08/09/2023 9:10 am, Mike Monett VE3BTI wrote:
I recently changed the overhead fluorescent lamps for LED replacements.

Very soon, I noticed they were flickering a lot more the the old
fluorescents.

They flicker on the slightest line disturbance, from someone turning on a
microwave to who knows what outside the building. It turns out the
bandwidth of LEDs is much higher than gas lamps. Good to know if you\'re in
the spying business, but not good in the shop.

I studied various methods of supplying clean power, from LifePO4 batteries
to my own solar array. Very expensive, and can\'t avoid batteries.

I settled on a brute force attack, using a dimmer and huge capacitors. The
dimmer is needed as a PWM to reduce the rectified line voltage from 160
volts down to 125 volts. The dimmer also allows to dim the LEDs to arrive
at a more comfortable illumination. They are very bright.

The lED lamps contain their own bridge rectifier to convert the AC line
voltage to DC to drive the lamps.

There is one trick in the circuit that is of note, and is why I am posting
the circuit here.

It is necessary to break the dimmer AC line between the delay pot and the
triac to insert a 10 ohm resistor. The resistor cuts down on the surge
current during startup, but it causes a drop in line voltage. If this drop
is applied to the delay pot, the circuit goes haywire during startup.

Note the 1N4007 diodes are replaced by a regular bridge rectifier with
suitable ratings. It is easier to model using 1N4007s than trying to find a
bridge rectifier in LTspice.

The circuit has been tested on LTspice IV and XII. I will never run QSpice
since is requires MS 10-11 and 64 bits. I got off the Microsoft merry-go-
round at Win7, and I am perfectly content to stay there.

From past experience it may be necessary to fiddle with the Model
statements to get the program to load in LTspice. The line wrap in the
newsgroup creates havoc on LTspice.

Here\'s the ASC file:

Version 4
SHEET 1 1684 680
WIRE 176 16 -16 16
WIRE 224 16 176 16
WIRE 368 16 304 16
WIRE 432 16 368 16
WIRE 480 16 432 16
WIRE 592 16 544 16
WIRE 368 32 368 16
WIRE 176 64 176 16
WIRE -16 112 -16 16
WIRE 368 128 368 112
WIRE 464 128 368 128
WIRE 480 128 464 128
WIRE 592 128 592 16
WIRE 592 128 544 128
WIRE 624 128 592 128
WIRE 640 128 624 128
WIRE 656 128 640 128
WIRE 752 128 736 128
WIRE 864 128 752 128
WIRE 368 144 368 128
WIRE 640 160 640 128
WIRE 864 160 864 128
WIRE 752 176 752 128
WIRE 176 208 176 144
WIRE 224 208 176 208
WIRE 256 208 224 208
WIRE 176 224 176 208
WIRE 432 272 432 16
WIRE 480 272 432 272
WIRE 592 272 544 272
WIRE 640 272 640 240
WIRE 640 272 592 272
WIRE 720 272 640 272
WIRE 752 272 752 240
WIRE 752 272 720 272
WIRE 864 272 864 240
WIRE 864 272 752 272
WIRE -16 304 -16 192
WIRE 176 304 176 288
WIRE 176 304 -16 304
WIRE 368 304 368 208
WIRE 368 304 176 304
WIRE -16 320 -16 304
WIRE 464 352 464 128
WIRE 480 352 464 352
WIRE 592 352 592 272
WIRE 592 352 544 352
FLAG -16 320 0
FLAG 368 16 A
FLAG 224 208 VC1
FLAG 752 128 C
FLAG 720 272 D
FLAG 368 128 B
FLAG 624 128 E
SYMBOL misc\\\\DIAC 320 176 R90
WINDOW 0 0 32 VBottom 2
WINDOW 3 64 32 VTop 2
WINDOW 123 92 32 VTop 2
SYMATTR InstName Q1
SYMATTR Value2 VK=30
SYMBOL voltage -16 96 R0
WINDOW 0 10 -1 Left 2
WINDOW 3 -65 137 Left 2
WINDOW 123 0 0 Left 2
WINDOW 39 0 0 Left 2
SYMATTR InstName V1
SYMATTR Value SINE(0 166 60 0 0 0 20)
SYMBOL res 160 160 M180
WINDOW 0 36 76 Left 2
WINDOW 3 36 40 Left 2
SYMATTR InstName R1
SYMATTR Value 200k
SYMBOL cap 160 224 R0
SYMATTR InstName C1
SYMATTR Value .062u
SYMBOL misc\\\\TRIAC 336 144 R0
SYMATTR InstName U1
SYMBOL diode 544 0 R90
WINDOW 0 0 32 VBottom 2
WINDOW 3 32 32 VTop 2
SYMATTR InstName D1
SYMATTR Value 1N4007
SYMBOL diode 544 112 R90
WINDOW 0 0 32 VBottom 2
WINDOW 3 32 32 VTop 2
SYMATTR InstName D2
SYMATTR Value 1N4007
SYMBOL diode 480 288 R270
WINDOW 0 32 32 VTop 2
WINDOW 3 0 32 VBottom 2
SYMATTR InstName D3
SYMATTR Value 1N4007
SYMBOL diode 480 368 R270
WINDOW 0 32 32 VTop 2
WINDOW 3 0 32 VBottom 2
SYMATTR InstName D4
SYMATTR Value 1N4007
SYMBOL res 624 144 R0
SYMATTR InstName R2
SYMATTR Value 230
SYMBOL cap 736 176 R0
SYMATTR InstName C2
SYMATTR Value 1640uf
SYMBOL res 752 112 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R3
SYMATTR Value 0.1
SYMBOL res 352 16 R0
SYMATTR InstName R4
SYMATTR Value 1k
SYMBOL res 320 0 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R5
SYMATTR Value 10
SYMBOL res 848 144 R0
SYMATTR InstName R6
SYMATTR Value 100k
TEXT 40 -48 Left 2 !.tran 0 500ms 0 10u
TEXT -376 280 Left 2 !.subckt DIAC T1 T2\\n* default parameters\\n.param RS=
10 ; series resistance\\n.param VK=20 ; breakdown voltage\\nQ1 N002 N001 T2 0
PN\\nQ2 N001 N002 N005 0 NP\\nR1 N002 N004 {20K*(VK-1)}\\nR2 N004 T2 9.5K\\nR3
N002 N005 9.5K\\nQ3 N004 N003 N005 0 PN\\nQ4 N003 N004 T2 0 NP\\nR4 T1 N005
{RS}\\n.model PN NPN Cjc=10p Cje=10p\\n.model NP PNP Cjc=10p Cje=10p\\n.ends
DIAC
TEXT -376 16 Left 2 !.subckt TRIAC MT2 G MT1\\n.param R=10K\\nQ1 N001 G MT1 0
NP\\nQ2 N001 N002 MT2 0 NP\\nQ3 N002 N001 MT1 0 PN\\nQ4 G N001 MT2 0 PN\\nR1
MT2 N002 {R}\\nR2 G MT1 {R}\\n.model PN NPN Cjc=10p Cje=10p\\n.model NP PNP
Cjc=10p Cje=10p\\n.ends TRIAC
TEXT 40 -80 Left 2 ;\'DIAC TRIAC Light Dimmer Step RDim
TEXT 64 336 Left 2 ;200e3*.062e-6 = 0.0124 seconds
TEXT -56 432 Left 2 !.model 1N4007 D(Is=14.11n N=1.984 Rs=33.89m Ikf=94.81
Xti=3 Eg=1.11 Cjo=25.89p \\n+M=.44 Vj=.3245 Fc=.5 Bv=1500 Ibv=10u Tt=5.7u
Iave=1A Vpk=1500 mfg=Motorola type=silicon)
TEXT 632 312 Left 2 ;100e3*1540e-6= 154 seconds

The PLT file

[Transient Analysis]
{
Npanes: 2
Active Pane: 1
{
traces: 3 {524293,0,\"V(d,c)\"} {524294,0,\"V(d,e)\"} {34603012,1,\"I
(R3)\"}
X: (\'m\',0,0,0.05,0.5)
Y[0]: (\' \',0,0,10,130)
Y[1]: (\' \',0,-4,2,22)
Volts: (\' \',0,0,0,0,10,130)
Amps: (\' \',0,0,0,-4,2,22)
Log: 0 0 0
GridStyle: 1
},
{
traces: 2 {524291,0,\"V(b)\"} {524290,0,\"V(a)\"}
X: (\'m\',0,0,0.05,0.5)
Y[0]: (\' \',0,-180,30,180)
Y[1]: (\' \',0,1e+308,3,-1e+308)
Volts: (\' \',0,0,0,-180,30,180)
Log: 0 0 0
GridStyle: 1
}
}
Click to expand...

What do you use the waste heat in R5 for, boiling water for tea?

piglet
 
On 08/09/2023 11:18 am, piglet wrote:
On 08/09/2023 9:10 am, Mike Monett VE3BTI wrote:
I recently changed the overhead fluorescent lamps for LED replacements.

Very soon, I noticed they were flickering a lot more the the old
fluorescents.

They flicker on the slightest line disturbance, from someone turning on a
microwave to who knows what outside the building. It turns out the
bandwidth of LEDs is much higher than gas lamps. Good to know if
you\'re in
the spying business, but not good in the shop.

I studied various methods of supplying clean power, from LifePO4
batteries
to my own solar array. Very expensive, and can\'t avoid batteries.

I settled on a brute force attack, using a dimmer and huge capacitors.
The
dimmer is needed as a PWM to reduce the rectified line voltage from 160
volts down to 125 volts. The dimmer also allows to dim the LEDs to arrive
at a more comfortable illumination. They are very bright.

The lED lamps contain their own bridge rectifier to convert the AC line
voltage to DC to drive the lamps.

There is one trick in the circuit that is of note, and is why I am
posting
the circuit here.

It is necessary to break the dimmer AC line between the delay pot and the
triac to insert a 10 ohm resistor. The resistor cuts down on the surge
current during startup, but it causes a drop in line voltage. If this
drop
is applied to the delay pot, the circuit goes haywire during startup.

Note the 1N4007 diodes are replaced by a regular bridge rectifier with
suitable ratings. It is easier to model using 1N4007s than trying to
find a
bridge rectifier in LTspice.

The circuit has been tested on LTspice IV and XII. I will never run
QSpice
since is requires MS 10-11 and 64 bits. I got off the Microsoft merry-go-
round at Win7, and I am perfectly content to stay there.

 From past experience it may be necessary to fiddle with the Model
statements to get the program to load in LTspice. The line wrap in the
newsgroup creates havoc on LTspice.

Here\'s the ASC file:

Version 4
SHEET 1 1684 680
WIRE 176 16 -16 16
WIRE 224 16 176 16
WIRE 368 16 304 16
WIRE 432 16 368 16
WIRE 480 16 432 16
WIRE 592 16 544 16
WIRE 368 32 368 16
WIRE 176 64 176 16
WIRE -16 112 -16 16
WIRE 368 128 368 112
WIRE 464 128 368 128
WIRE 480 128 464 128
WIRE 592 128 592 16
WIRE 592 128 544 128
WIRE 624 128 592 128
WIRE 640 128 624 128
WIRE 656 128 640 128
WIRE 752 128 736 128
WIRE 864 128 752 128
WIRE 368 144 368 128
WIRE 640 160 640 128
WIRE 864 160 864 128
WIRE 752 176 752 128
WIRE 176 208 176 144
WIRE 224 208 176 208
WIRE 256 208 224 208
WIRE 176 224 176 208
WIRE 432 272 432 16
WIRE 480 272 432 272
WIRE 592 272 544 272
WIRE 640 272 640 240
WIRE 640 272 592 272
WIRE 720 272 640 272
WIRE 752 272 752 240
WIRE 752 272 720 272
WIRE 864 272 864 240
WIRE 864 272 752 272
WIRE -16 304 -16 192
WIRE 176 304 176 288
WIRE 176 304 -16 304
WIRE 368 304 368 208
WIRE 368 304 176 304
WIRE -16 320 -16 304
WIRE 464 352 464 128
WIRE 480 352 464 352
WIRE 592 352 592 272
WIRE 592 352 544 352
FLAG -16 320 0
FLAG 368 16 A
FLAG 224 208 VC1
FLAG 752 128 C
FLAG 720 272 D
FLAG 368 128 B
FLAG 624 128 E
SYMBOL misc\\\\DIAC 320 176 R90
WINDOW 0 0 32 VBottom 2
WINDOW 3 64 32 VTop 2
WINDOW 123 92 32 VTop 2
SYMATTR InstName Q1
SYMATTR Value2 VK=30
SYMBOL voltage -16 96 R0
WINDOW 0 10 -1 Left 2
WINDOW 3 -65 137 Left 2
WINDOW 123 0 0 Left 2
WINDOW 39 0 0 Left 2
SYMATTR InstName V1
SYMATTR Value SINE(0 166 60 0 0 0 20)
SYMBOL res 160 160 M180
WINDOW 0 36 76 Left 2
WINDOW 3 36 40 Left 2
SYMATTR InstName R1
SYMATTR Value 200k
SYMBOL cap 160 224 R0
SYMATTR InstName C1
SYMATTR Value .062u
SYMBOL misc\\\\TRIAC 336 144 R0
SYMATTR InstName U1
SYMBOL diode 544 0 R90
WINDOW 0 0 32 VBottom 2
WINDOW 3 32 32 VTop 2
SYMATTR InstName D1
SYMATTR Value 1N4007
SYMBOL diode 544 112 R90
WINDOW 0 0 32 VBottom 2
WINDOW 3 32 32 VTop 2
SYMATTR InstName D2
SYMATTR Value 1N4007
SYMBOL diode 480 288 R270
WINDOW 0 32 32 VTop 2
WINDOW 3 0 32 VBottom 2
SYMATTR InstName D3
SYMATTR Value 1N4007
SYMBOL diode 480 368 R270
WINDOW 0 32 32 VTop 2
WINDOW 3 0 32 VBottom 2
SYMATTR InstName D4
SYMATTR Value 1N4007
SYMBOL res 624 144 R0
SYMATTR InstName R2
SYMATTR Value 230
SYMBOL cap 736 176 R0
SYMATTR InstName C2
SYMATTR Value 1640uf
SYMBOL res 752 112 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R3
SYMATTR Value 0.1
SYMBOL res 352 16 R0
SYMATTR InstName R4
SYMATTR Value 1k
SYMBOL res 320 0 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R5
SYMATTR Value 10
SYMBOL res 848 144 R0
SYMATTR InstName R6
SYMATTR Value 100k
TEXT 40 -48 Left 2 !.tran 0 500ms 0 10u
TEXT -376 280 Left 2 !.subckt DIAC T1 T2\\n* default parameters\\n.param
RS=
10 ; series resistance\\n.param VK=20 ; breakdown voltage\\nQ1 N002 N001
T2 0
PN\\nQ2 N001 N002 N005 0 NP\\nR1 N002 N004 {20K*(VK-1)}\\nR2 N004 T2
9.5K\\nR3
N002 N005 9.5K\\nQ3 N004 N003 N005 0 PN\\nQ4 N003 N004 T2 0 NP\\nR4 T1 N005
{RS}\\n.model PN NPN Cjc=10p Cje=10p\\n.model NP PNP Cjc=10p Cje=10p\\n.ends
DIAC
TEXT -376 16 Left 2 !.subckt TRIAC MT2 G MT1\\n.param R=10K\\nQ1 N001 G
MT1 0
NP\\nQ2 N001 N002 MT2 0 NP\\nQ3 N002 N001 MT1 0 PN\\nQ4 G N001 MT2 0 PN\\nR1
MT2 N002 {R}\\nR2 G MT1 {R}\\n.model PN NPN Cjc=10p Cje=10p\\n.model NP PNP
Cjc=10p Cje=10p\\n.ends TRIAC
TEXT 40 -80 Left 2 ;\'DIAC TRIAC Light Dimmer Step RDim
TEXT 64 336 Left 2 ;200e3*.062e-6 = 0.0124 seconds
TEXT -56 432 Left 2 !.model 1N4007 D(Is=14.11n N=1.984 Rs=33.89m
Ikf=94.81
Xti=3 Eg=1.11 Cjo=25.89p \\n+M=.44 Vj=.3245 Fc=.5 Bv=1500 Ibv=10u Tt=5.7u
Iave=1A Vpk=1500 mfg=Motorola type=silicon)
TEXT 632 312 Left 2 ;100e3*1540e-6= 154 seconds

The PLT file

[Transient Analysis]
{
    Npanes: 2
    Active Pane: 1
    {
       traces: 3 {524293,0,\"V(d,c)\"} {524294,0,\"V(d,e)\"} {34603012,1,\"I
(R3)\"}
       X: (\'m\',0,0,0.05,0.5)
       Y[0]: (\' \',0,0,10,130)
       Y[1]: (\' \',0,-4,2,22)
       Volts: (\' \',0,0,0,0,10,130)
       Amps: (\' \',0,0,0,-4,2,22)
       Log: 0 0 0
       GridStyle: 1
    },
    {
       traces: 2 {524291,0,\"V(b)\"} {524290,0,\"V(a)\"}
       X: (\'m\',0,0,0.05,0.5)
       Y[0]: (\' \',0,-180,30,180)
       Y[1]: (\' \',0,1e+308,3,-1e+308)
       Volts: (\' \',0,0,0,-180,30,180)
       Log: 0 0 0
       GridStyle: 1
    }
}



What do you use the waste heat in R5 for, boiling water for tea?

piglet
Click to expand...

The model you used for 1N4007 has something very wrong - if I replace
with one of the 600V types included with LTSpice then the crazy currents
disappear and the circuit does more as you describe. Have you checked
Pdiss in R4?

piglet
 
On 9/8/2023 1:10 AM, Mike Monett VE3BTI wrote:
I recently changed the overhead fluorescent lamps for LED replacements.

Very soon, I noticed they were flickering a lot more the the old
fluorescents.
Click to expand...

Use a dimmer designed for LED lighting. They will typically
also have a \"dimmer low end\" than conventional dimmers.
LEDs that flicker on a simple switched line are probably of
poor quality.

They flicker on the slightest line disturbance, from someone turning on a
microwave to who knows what outside the building. It turns out the
bandwidth of LEDs is much higher than gas lamps. Good to know if you\'re in
the spying business, but not good in the shop.

I studied various methods of supplying clean power, from LifePO4 batteries
to my own solar array. Very expensive, and can\'t avoid batteries.

I settled on a brute force attack, using a dimmer and huge capacitors. The
dimmer is needed as a PWM to reduce the rectified line voltage from 160
volts down to 125 volts. The dimmer also allows to dim the LEDs to arrive
at a more comfortable illumination. They are very bright.

The lED lamps contain their own bridge rectifier to convert the AC line
voltage to DC to drive the lamps.
Click to expand...
 
On Friday, September 8, 2023 at 6:56:39 AM UTC-4, Don Y wrote:
On 9/8/2023 1:10 AM, Mike Monett VE3BTI wrote:
I recently changed the overhead fluorescent lamps for LED replacements.

Very soon, I noticed they were flickering a lot more the the old
fluorescents.
Use a dimmer designed for LED lighting. They will typically
also have a \"dimmer low end\" than conventional dimmers.
LEDs that flicker on a simple switched line are probably of
poor quality.
Click to expand...

I bought an LED lighting fixture and the dimmer specified on the package as compatible. It wasn\'t. It was all crap. I contacted the manufacturer and their response was to return the product. They don\'t care. They sell you gold on the box, but crap in it.

--

Rick C.

- Get 1,000 miles of free Supercharging
- Tesla referral code - https://ts.la/richard11209
 
On Fri, 8 Sep 2023 08:10:41 -0000 (UTC), Mike Monett VE3BTI
<spamme@not.com> wrote:

I recently changed the overhead fluorescent lamps for LED replacements.

Very soon, I noticed they were flickering a lot more the the old
fluorescents.

They flicker on the slightest line disturbance, from someone turning on a
microwave to who knows what outside the building. It turns out the
bandwidth of LEDs is much higher than gas lamps. Good to know if you\'re in
the spying business, but not good in the shop.
Click to expand...

I doubt that the fluorescents are much slower, at visual speeds, than
LEDs. You can verify that with a photodetector and an ocilloscope.

Maybe you have cheap flourescent-replacement tubes.

I studied various methods of supplying clean power, from LifePO4 batteries
to my own solar array. Very expensive, and can\'t avoid batteries.

I settled on a brute force attack, using a dimmer and huge capacitors. The
dimmer is needed as a PWM to reduce the rectified line voltage from 160
volts down to 125 volts. The dimmer also allows to dim the LEDs to arrive
at a more comfortable illumination. They are very bright.

The lED lamps contain their own bridge rectifier to convert the AC line
voltage to DC to drive the lamps.

There is one trick in the circuit that is of note, and is why I am posting
the circuit here.

It is necessary to break the dimmer AC line between the delay pot and the
triac to insert a 10 ohm resistor. The resistor cuts down on the surge
current during startup, but it causes a drop in line voltage. If this drop
is applied to the delay pot, the circuit goes haywire during startup.

Note the 1N4007 diodes are replaced by a regular bridge rectifier with
suitable ratings. It is easier to model using 1N4007s than trying to find a
bridge rectifier in LTspice.

The circuit has been tested on LTspice IV and XII. I will never run QSpice
since is requires MS 10-11 and 64 bits. I got off the Microsoft merry-go-
round at Win7, and I am perfectly content to stay there.

From past experience it may be necessary to fiddle with the Model
statements to get the program to load in LTspice. The line wrap in the
newsgroup creates havoc on LTspice.

Here\'s the ASC file:

Version 4
SHEET 1 1684 680
WIRE 176 16 -16 16
WIRE 224 16 176 16
WIRE 368 16 304 16
WIRE 432 16 368 16
WIRE 480 16 432 16
WIRE 592 16 544 16
WIRE 368 32 368 16
WIRE 176 64 176 16
WIRE -16 112 -16 16
WIRE 368 128 368 112
WIRE 464 128 368 128
WIRE 480 128 464 128
WIRE 592 128 592 16
WIRE 592 128 544 128
WIRE 624 128 592 128
WIRE 640 128 624 128
WIRE 656 128 640 128
WIRE 752 128 736 128
WIRE 864 128 752 128
WIRE 368 144 368 128
WIRE 640 160 640 128
WIRE 864 160 864 128
WIRE 752 176 752 128
WIRE 176 208 176 144
WIRE 224 208 176 208
WIRE 256 208 224 208
WIRE 176 224 176 208
WIRE 432 272 432 16
WIRE 480 272 432 272
WIRE 592 272 544 272
WIRE 640 272 640 240
WIRE 640 272 592 272
WIRE 720 272 640 272
WIRE 752 272 752 240
WIRE 752 272 720 272
WIRE 864 272 864 240
WIRE 864 272 752 272
WIRE -16 304 -16 192
WIRE 176 304 176 288
WIRE 176 304 -16 304
WIRE 368 304 368 208
WIRE 368 304 176 304
WIRE -16 320 -16 304
WIRE 464 352 464 128
WIRE 480 352 464 352
WIRE 592 352 592 272
WIRE 592 352 544 352
FLAG -16 320 0
FLAG 368 16 A
FLAG 224 208 VC1
FLAG 752 128 C
FLAG 720 272 D
FLAG 368 128 B
FLAG 624 128 E
SYMBOL misc\\\\DIAC 320 176 R90
WINDOW 0 0 32 VBottom 2
WINDOW 3 64 32 VTop 2
WINDOW 123 92 32 VTop 2
SYMATTR InstName Q1
SYMATTR Value2 VK=30
SYMBOL voltage -16 96 R0
WINDOW 0 10 -1 Left 2
WINDOW 3 -65 137 Left 2
WINDOW 123 0 0 Left 2
WINDOW 39 0 0 Left 2
SYMATTR InstName V1
SYMATTR Value SINE(0 166 60 0 0 0 20)
SYMBOL res 160 160 M180
WINDOW 0 36 76 Left 2
WINDOW 3 36 40 Left 2
SYMATTR InstName R1
SYMATTR Value 200k
SYMBOL cap 160 224 R0
SYMATTR InstName C1
SYMATTR Value .062u
SYMBOL misc\\\\TRIAC 336 144 R0
SYMATTR InstName U1
SYMBOL diode 544 0 R90
WINDOW 0 0 32 VBottom 2
WINDOW 3 32 32 VTop 2
SYMATTR InstName D1
SYMATTR Value 1N4007
SYMBOL diode 544 112 R90
WINDOW 0 0 32 VBottom 2
WINDOW 3 32 32 VTop 2
SYMATTR InstName D2
SYMATTR Value 1N4007
SYMBOL diode 480 288 R270
WINDOW 0 32 32 VTop 2
WINDOW 3 0 32 VBottom 2
SYMATTR InstName D3
SYMATTR Value 1N4007
SYMBOL diode 480 368 R270
WINDOW 0 32 32 VTop 2
WINDOW 3 0 32 VBottom 2
SYMATTR InstName D4
SYMATTR Value 1N4007
SYMBOL res 624 144 R0
SYMATTR InstName R2
SYMATTR Value 230
SYMBOL cap 736 176 R0
SYMATTR InstName C2
SYMATTR Value 1640uf
SYMBOL res 752 112 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R3
SYMATTR Value 0.1
SYMBOL res 352 16 R0
SYMATTR InstName R4
SYMATTR Value 1k
SYMBOL res 320 0 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R5
SYMATTR Value 10
SYMBOL res 848 144 R0
SYMATTR InstName R6
SYMATTR Value 100k
TEXT 40 -48 Left 2 !.tran 0 500ms 0 10u
TEXT -376 280 Left 2 !.subckt DIAC T1 T2\\n* default parameters\\n.param RS=
10 ; series resistance\\n.param VK=20 ; breakdown voltage\\nQ1 N002 N001 T2 0
PN\\nQ2 N001 N002 N005 0 NP\\nR1 N002 N004 {20K*(VK-1)}\\nR2 N004 T2 9.5K\\nR3
N002 N005 9.5K\\nQ3 N004 N003 N005 0 PN\\nQ4 N003 N004 T2 0 NP\\nR4 T1 N005
{RS}\\n.model PN NPN Cjc=10p Cje=10p\\n.model NP PNP Cjc=10p Cje=10p\\n.ends
DIAC
TEXT -376 16 Left 2 !.subckt TRIAC MT2 G MT1\\n.param R=10K\\nQ1 N001 G MT1 0
NP\\nQ2 N001 N002 MT2 0 NP\\nQ3 N002 N001 MT1 0 PN\\nQ4 G N001 MT2 0 PN\\nR1
MT2 N002 {R}\\nR2 G MT1 {R}\\n.model PN NPN Cjc=10p Cje=10p\\n.model NP PNP
Cjc=10p Cje=10p\\n.ends TRIAC
TEXT 40 -80 Left 2 ;\'DIAC TRIAC Light Dimmer Step RDim
TEXT 64 336 Left 2 ;200e3*.062e-6 = 0.0124 seconds
TEXT -56 432 Left 2 !.model 1N4007 D(Is=14.11n N=1.984 Rs=33.89m Ikf=94.81
Xti=3 Eg=1.11 Cjo=25.89p \\n+M=.44 Vj=.3245 Fc=.5 Bv=1500 Ibv=10u Tt=5.7u
Iave=1A Vpk=1500 mfg=Motorola type=silicon)
TEXT 632 312 Left 2 ;100e3*1540e-6= 154 seconds

The PLT file

[Transient Analysis]
{
Npanes: 2
Active Pane: 1
{
traces: 3 {524293,0,\"V(d,c)\"} {524294,0,\"V(d,e)\"} {34603012,1,\"I
(R3)\"}
X: (\'m\',0,0,0.05,0.5)
Y[0]: (\' \',0,0,10,130)
Y[1]: (\' \',0,-4,2,22)
Volts: (\' \',0,0,0,0,10,130)
Amps: (\' \',0,0,0,-4,2,22)
Log: 0 0 0
GridStyle: 1
},
{
traces: 2 {524291,0,\"V(b)\"} {524290,0,\"V(a)\"}
X: (\'m\',0,0,0.05,0.5)
Y[0]: (\' \',0,-180,30,180)
Y[1]: (\' \',0,1e+308,3,-1e+308)
Volts: (\' \',0,0,0,-180,30,180)
Log: 0 0 0
GridStyle: 1
}
}
Click to expand...
 
On Fri, 8 Sep 2023 08:10:41 -0000 (UTC), Mike Monett VE3BTI
<spamme@not.com> wrote:

I recently changed the overhead fluorescent lamps for LED replacements.

Very soon, I noticed they were flickering a lot more the the old
fluorescents.

snip
The lED lamps contain their own bridge rectifier to convert the AC line
voltage to DC to drive the lamps.

snip
Click to expand...

Mike, there are many fluorescent replacement types of LED lamp.
At this low (and usually fixed) power level, it\'s possible to
skin this cat any number of ways.

If you use a variac to evaluate brightness vs line voltage on
the lamps you are using, you\'ll see the range of voltages
required to perform the dimming function.

I think you\'ll be surprised at just how low these voltage
values can be and how narrow the adjustment range is.
Only types that are designed for dimming, or dimmers
designed for LEDs can give you satisfactory performance.

R4 . . . . this is one cat that isn\'t skinned properly.

RL
 
legg <legg@nospam.magma.ca> wrote:

snip
The lED lamps contain their own bridge rectifier to convert the AC line
voltage to DC to drive the lamps.

snip

Mike, there are many fluorescent replacement types of LED lamp.
At this low (and usually fixed) power level, it\'s possible to
skin this cat any number of ways.

If you use a variac to evaluate brightness vs line voltage on
the lamps you are using, you\'ll see the range of voltages
required to perform the dimming function.

I think you\'ll be surprised at just how low these voltage
values can be and how narrow the adjustment range is.
Only types that are designed for dimming, or dimmers
designed for LEDs can give you satisfactory performance.

R4 . . . . this is one cat that isn\'t skinned properly.

RL
Click to expand...

Thanks for your message.

I am interested in eliminating flicker due to line transients. A capacitor
stores energy and supplies it to the LED during a transient.

Ordinary dimmers are not intended to drive capacitors. This will be the
first time. I will have to see how they perform but I am pretty confident
they will work in this application.

I am not interested in actually dimming the light. I have a 0 - 300v supply
that I can use to see how the LED lamps perform with DC. I understand they
operate over a narrow range, much like a diode, as they are basically
current driven.

I agree with you. R4 may not be needed. I included it as I didn\'t know how
it would affect the operation of the circuit. Changing it to 1e6 ohms made
no difference.



--
MRM
 
fredag den 8. september 2023 kl. 20.49.57 UTC+2 skrev Mike Monett VE3BTI:
legg <le...@nospam.magma.ca> wrote:

snip
The lED lamps contain their own bridge rectifier to convert the AC line
voltage to DC to drive the lamps.

snip

Mike, there are many fluorescent replacement types of LED lamp.
At this low (and usually fixed) power level, it\'s possible to
skin this cat any number of ways.

If you use a variac to evaluate brightness vs line voltage on
the lamps you are using, you\'ll see the range of voltages
required to perform the dimming function.

I think you\'ll be surprised at just how low these voltage
values can be and how narrow the adjustment range is.
Only types that are designed for dimming, or dimmers
designed for LEDs can give you satisfactory performance.

R4 . . . . this is one cat that isn\'t skinned properly.

RL
Thanks for your message.

I am interested in eliminating flicker due to line transients. A capacitor
stores energy and supplies it to the LED during a transient.

Ordinary dimmers are not intended to drive capacitors. This will be the
first time. I will have to see how they perform but I am pretty confident
they will work in this application.

I am not interested in actually dimming the light. I have a 0 - 300v supply
that I can use to see how the LED lamps perform with DC. I understand they
operate over a narrow range, much like a diode, as they are basically
current driven.

I agree with you. R4 may not be needed. I included it as I didn\'t know how
it would affect the operation of the circuit. Changing it to 1e6 ohms made
no difference.
Click to expand...

most LED lamps have a build in constant current driver so they will be the same
brightness at any voltage high enough for the LEDs and regulation

or that they have a capacitive dropper that will only work on DC and have a terrible power factor
 
piglet <erichpwagner@hotmail.com> wrote:

The model you used for 1N4007 has something very wrong - if I replace
with one of the 600V types included with LTSpice then the crazy currents
disappear and the circuit does more as you describe. Have you checked
Pdiss in R4?

piglet
Click to expand...

VII doesn\'t have the 1N4007, so I got the model from LTspice IV. It shows a
PIV of 1,500 v. There are no 600 V versions in IV.

I see no crazy currents in IV or VII. Can you tell me more about what you are
seeing?

I tried to plot the power in R4 but had no luck in IV or VII. I tried to
calculate pwr(V(x), V(a)) but got 9.65e+307 with no units. So I have to
guess. I\'ll try a 2W wirewound.



--
MRM
 
piglet <erichpwagner@hotmail.com> wrote:

What do you use the waste heat in R5 for, boiling water for tea?

piglet
Click to expand...

I don\'t think it\'s that bad. Futher answer in next post.

--
MRM
 
Lasse Langwadt Christensen <langwadt@fonz.dk> wrote:

most LED lamps have a build in constant current driver so they will be
the same brightness at any voltage high enough for the LEDs and
regulation

or that they have a capacitive dropper that will only work on DC and
have a terrible power factor
Click to expand...

I checked. The only electronics on my LED lamps is a bridge rectifier.

A capacitive dropper will not work on DC.



--
MRM
 
fredag den 8. september 2023 kl. 21.29.18 UTC+2 skrev Mike Monett VE3BTI:
Lasse Langwadt Christensen <lang...@fonz.dk> wrote:

most LED lamps have a build in constant current driver so they will be
the same brightness at any voltage high enough for the LEDs and
regulation

or that they have a capacitive dropper that will only work on DC and
have a terrible power factor
I checked. The only electronics on my LED lamps is a bridge rectifier.

A capacitive dropper will not work on DC.
Click to expand...

obviously meant \"only work on AC\"
 
Lasse Langwadt Christensen <langwadt@fonz.dk> wrote:

fredag den 8. september 2023 kl. 21.29.18 UTC+2 skrev Mike Monett VE3BTI:
Lasse Langwadt Christensen <lang...@fonz.dk> wrote:

most LED lamps have a build in constant current driver so they will be
the same brightness at any voltage high enough for the LEDs and
regulation

or that they have a capacitive dropper that will only work on DC and
have a terrible power factor
I checked. The only electronics on my LED lamps is a bridge rectifier.

A capacitive dropper will not work on DC.

obviously meant \"only work on AC\"
Click to expand...

Why do you want to drop the voltage? There are the correct number of LEDs
in series needed to work at 120VAC.

I verified there is a bridge rectifier in the LED lamps. I found a web site
that disassembled a LED lamp and read the part number off the IC mounted on
a small pcb. It turned out to be a bridge rectifier.

The bridge rectifier in the LED lamps is needed to convert the AC line
voltage to rectified DC as the LEDS cannot run with reversed polarity.

There is no need for a constant current driver and none is installed.

Obviously, the LED lamps are sensitive to line voltage since they flicker
with slight disturbances in the line voltage.

If a constant current driver was installed, there would be no flickering
and no need for energy storage to ride out the transients.


--
MRM
 
On Friday, September 8, 2023 at 12:29:18 PM UTC-7, Mike Monett VE3BTI wrote:
Lasse Langwadt Christensen <lang...@fonz.dk> wrote:

most LED lamps have a build in constant current driver so they will be
the same brightness at any voltage high enough for the LEDs and
regulation

or that they have a capacitive dropper that will only work on DC and
have a terrible power factor
I checked. The only electronics on my LED lamps is a bridge rectifier.

A capacitive dropper will not work on DC.
Click to expand...

Usually, bridge-rectifier lamps are intended for fluorescent-type ballasts (inductive
current limiters passing AC); the ballast limits the current, the rectifiers
steer it so both half-cycles of the AC power the LEDs. There\'s
maximal (100 or 120 Hz) flicker, but at those frequencies, only
video cameras catch it as flicker.
 
On 09/09/2023 01:24, Mike Monett VE3BTI wrote:
Lasse Langwadt Christensen <langwadt@fonz.dk> wrote:

fredag den 8. september 2023 kl. 21.29.18 UTC+2 skrev Mike Monett VE3BTI:
Lasse Langwadt Christensen <lang...@fonz.dk> wrote:

most LED lamps have a build in constant current driver so they will be
the same brightness at any voltage high enough for the LEDs and
regulation

or that they have a capacitive dropper that will only work on DC and
have a terrible power factor
I checked. The only electronics on my LED lamps is a bridge rectifier.

A capacitive dropper will not work on DC.

obviously meant \"only work on AC\"

Why do you want to drop the voltage? There are the correct number of LEDs
in series needed to work at 120VAC.

I verified there is a bridge rectifier in the LED lamps. I found a web site
that disassembled a LED lamp and read the part number off the IC mounted on
a small pcb. It turned out to be a bridge rectifier.

The bridge rectifier in the LED lamps is needed to convert the AC line
voltage to rectified DC as the LEDS cannot run with reversed polarity.

There is no need for a constant current driver and none is installed.
Click to expand...

There should at least be a small choke or resistor in series with the
LED chain in addition otherwise they will be fried by the first line
transient high enough to exceed their breakdown voltage.

The weakest one will die and that takes out the entire chain. Better
designed LED lights have constant current drive and multiple chains.

Obviously, the LED lamps are sensitive to line voltage since they flicker
with slight disturbances in the line voltage.
Click to expand...

You seem to have a particularly cheap and nasty LED lamp then.

I have seen similar in the classic bulb configuration with a simple
rectifier, resistor and enough ~60 LEDs to take UK mains 240v. MTBF is
piss poor because the first LED to fail takes the entire thing down.

Better quality mains powered LED bulbs do have some capacitance and a
crude constant current supply. The ones I have are so good that even
with one phase down everything is at full brightness, but the problem
becomes obvious if I turn on the kettle which takes forever to boil.

If a constant current driver was installed, there would be no flickering
and no need for energy storage to ride out the transients.
Click to expand...

You would still need a capacitor somewhere to store energy for it to use.
Capacitors are often the weak link in LED bulbs as they get cooked.

--
Martin Brown
 
On Fri, 8 Sep 2023 08:10:41 -0000 (UTC), Mike Monett VE3BTI
<spamme@not.com> wrote:

Note the 1N4007 diodes are replaced by a regular bridge rectifier with
suitable ratings. It is easier to model using 1N4007s than trying to find a
bridge rectifier in LTspice.
Click to expand...

The 1N4007 works more like a PIN diode, the other 1N400x diodes are
normal diodes.
 
On Friday, September 8, 2023 at 11:25:43 AM UTC-4, John Larkin wrote:
On Fri, 8 Sep 2023 08:10:41 -0000 (UTC), Mike Monett VE3BTI
spa...@not.com> wrote:

I recently changed the overhead fluorescent lamps for LED replacements.

Very soon, I noticed they were flickering a lot more the the old
fluorescents.

They flicker on the slightest line disturbance, from someone turning on a
microwave to who knows what outside the building. It turns out the
bandwidth of LEDs is much higher than gas lamps. Good to know if you\'re in
the spying business, but not good in the shop.
I doubt that the fluorescents are much slower, at visual speeds, than
LEDs. You can verify that with a photodetector and an ocilloscope.

Maybe you have cheap flourescent-replacement tubes.
Click to expand...

Uh-huh. LEDs don\'t flicker. They\'re all powered by regulated switching ***current*** sources operating in the 20kHz-30kHz range. LEDs are not directly powered by voltage, and the current sources are immune to voltage fluctuation.

Maybe he bought a \"previously owned\" bulb for a discount, as in previous owner ran them for 10 years..
 
lørdag den 9. september 2023 kl. 14.46.48 UTC+2 skrev Fred Bloggs:
On Friday, September 8, 2023 at 11:25:43 AM UTC-4, John Larkin wrote:
On Fri, 8 Sep 2023 08:10:41 -0000 (UTC), Mike Monett VE3BTI
spa...@not.com> wrote:

I recently changed the overhead fluorescent lamps for LED replacements..

Very soon, I noticed they were flickering a lot more the the old
fluorescents.

They flicker on the slightest line disturbance, from someone turning on a
microwave to who knows what outside the building. It turns out the
bandwidth of LEDs is much higher than gas lamps. Good to know if you\'re in
the spying business, but not good in the shop.
I doubt that the fluorescents are much slower, at visual speeds, than
LEDs. You can verify that with a photodetector and an ocilloscope.

Maybe you have cheap flourescent-replacement tubes.
Uh-huh. LEDs don\'t flicker. They\'re all powered by regulated switching ***current*** sources operating in the 20kHz-30kHz range. LEDs are not directly powered by voltage, and the current sources are immune to voltage fluctuation.
Click to expand...

some are linear, enough LEDs in series to add up to most of the rectified line voltage
 
On Saturday, September 9, 2023 at 9:01:28 AM UTC-4, Lasse Langwadt Christensen wrote:
lørdag den 9. september 2023 kl. 14.46.48 UTC+2 skrev Fred Bloggs:
On Friday, September 8, 2023 at 11:25:43 AM UTC-4, John Larkin wrote:
On Fri, 8 Sep 2023 08:10:41 -0000 (UTC), Mike Monett VE3BTI
spa...@not.com> wrote:

I recently changed the overhead fluorescent lamps for LED replacements.

Very soon, I noticed they were flickering a lot more the the old
fluorescents.

They flicker on the slightest line disturbance, from someone turning on a
microwave to who knows what outside the building. It turns out the
bandwidth of LEDs is much higher than gas lamps. Good to know if you\'re in
the spying business, but not good in the shop.
I doubt that the fluorescents are much slower, at visual speeds, than
LEDs. You can verify that with a photodetector and an ocilloscope.

Maybe you have cheap flourescent-replacement tubes.
Uh-huh. LEDs don\'t flicker. They\'re all powered by regulated switching ***current*** sources operating in the 20kHz-30kHz range. LEDs are not directly powered by voltage, and the current sources are immune to voltage fluctuation.

some are linear, enough LEDs in series to add up to most of the rectified line voltage
Click to expand...

I\'m pretty sure they\'ve never used that method for the commodity lighting bulb market. Maybe for signs and indicator bulb types of applications where it has to be dirt cheap.
 
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