Joule Thief - still not working....

Well, I made an ugly deadbug circuit and I got some pretty good results. I
used an MPSA06 NPN transistor, R1=10k, C3=100pF, and the coil is a
Coiltronics DRQ74-101-R 100 uH 1A dual inductor. It's about 3/8" square and
1/4" high. Probably good for at least 5 watts. I have two jumbo white LEDs
on the output in series with a 47 ohm resistor. Otherwise my circuit is the
same as the LTSpice circuit I posted before. Here are the results:

1.58V 0.024A 38 mW 5.72V 4.4 mA 25 mW 66% eff

2.11V 0.04A 84 mW 6.25V 8.9 mA 56 mW 66% eff

3.10V 0.06A 186 mW 7.23V 19 mA 140 mW 75% eff

4.24V 0.08A 339 mW 8.23V 32 mA 263 mW 77% eff

5.07V 0.096A 487 mW 8.86V 41 mA 362 mW 74% eff

I measured 130 kHz at 3 VDC input. No sign of heating on any of the
components. 99 mV P-P ripple on output. The LEDs remain barely lit at 800
mV input.

I also made a simulation for a high-power version that uses a MOSFET. 85%
efficient at 41 watts output with 12 VDC input. I'll post it if anyone is
interested.

Paul
 
On Aug 3, 5:25 am, "bw" <bweg...@hotmail.com> wrote:
The Schottky diode D5 and filter capacitor on the output limit the high
current spikes that otherwise go through the LEDs. Another Schottky D7
limits the reverse voltage spikes. These spikes could damage the LEDs.

I've not tested these. I've not noticed LED damage after several days. I did
try hanging a 6 volt zener on the base, which does protect the BE junction
but cuts efficiency.
Click to expand...
I haven't seen any real current spikes on the LEDs.

Besides, most LED datasheets I've seen show that you can run
them on 100mA pulses so I think that so long as the average power
is within range then nothing's going to happen..

What *does* kill your LEDs is putting your multimeter between
LEDs/ground to measure the current going through them, then
forgetting to switch off the battery *before* disconnecting the
multimeter.

C1 up to a massive voltage when there's no load and when
you reconnect the circuit you get a *very* bright flash from
the LEDs. Then not much else. Ever again. :_(

(Yeah, I know ... I need to get some one ohm resistors so
I can just put them inline and measure the voltage drop across
them).
 
On Aug 3, 9:21 am, fungus <openglMYSO...@artlum.com> wrote:
C1 charges up to a massive voltage...
Click to expand...
....I guess I could also put a 1k resistor across C1 to discharge
it when I turn off the battery.
 
fungus wrote:
On Aug 3, 9:21 am, fungus <openglMYSO...@artlum.com> wrote:
C1 charges up to a massive voltage...


...I guess I could also put a 1k resistor across C1 to discharge
it when I turn off the battery.
Click to expand...
Make the 1k resistor bigger - more like 100k - 1M ohm, or use a zener
diode to control the voltage rise.
 
On Sun, 02 Aug 2009 18:15:08 -0500, John Fields wrote:
On Sun, 02 Aug 2009 17:20:07 +1200, greg <greg@cosc.canterbury.ac.nz
fungus wrote:

I assume there has to be actual air there, not a stick, so whatever
I wind it onto has to be removed, right?

No, anything non-metallic and non-conductive --
wood, plastic, cardboard, etc. -- should make
very little difference.

IME that's not true.

A couple of hundred years ago (it seems) I built a 2kW CW ultrasonic
system where I used a piece of PVC pipe as a former to wind the loading
coil for the transducer and when we fired it up and tuned the system to
resonance, the pipe melted.

"Dissipation factor", I later learned, was what had bitten me on the
ass, and I solved the problem by cannibalizing the ceramic (steatite)
core of an ARC5's loading coil and winding it to get the inductance we
needed for resonance at 40kHz.

I once tried to build a simple buck converter; for the output coil
Click to expand...
all that was handy was the 3-4" dia. core from a spool of factory
wire.

It worked real good, until the plastic melted. ;-)

Cheers!
Rich
 
David Eather wrote:
fungus wrote:
On Aug 3, 9:21 am, fungus <openglMYSO...@artlum.com> wrote:
C1 charges up to a massive voltage...


...I guess I could also put a 1k resistor across C1 to discharge
it when I turn off the battery.

Make the 1k resistor bigger - more like 100k - 1M ohm, or use a zener
diode to control the voltage rise.
Click to expand...

The zener will be the most useful - get a value larger than the voltage
going through the LED's (IIRC that's about 18 volts) and put it across
the cap. It will conduct whenever the voltage rises above the zener
voltage - so clamping the maximum voltage on the cap. A small resistor
in series with the LEDs will also help a lot (something like 68 to 100
ohms).
 
In article <pan.2009.08.04.00.31.08.757860@example.net>, Rich Grise wrote:
On Sun, 02 Aug 2009 18:15:08 -0500, John Fields wrote:
On Sun, 02 Aug 2009 17:20:07 +1200, greg <greg@cosc.canterbury.ac.nz
fungus wrote:

I assume there has to be actual air there, not a stick, so whatever
I wind it onto has to be removed, right?

No, anything non-metallic and non-conductive --
wood, plastic, cardboard, etc. -- should make
very little difference.

IME that's not true.

A couple of hundred years ago (it seems) I built a 2kW CW ultrasonic
system where I used a piece of PVC pipe as a former to wind the loading
coil for the transducer and when we fired it up and tuned the system to
resonance, the pipe melted.

"Dissipation factor", I later learned, was what had bitten me on the
ass, and I solved the problem by cannibalizing the ceramic (steatite)
core of an ARC5's loading coil and winding it to get the inductance we
needed for resonance at 40kHz.

I once tried to build a simple buck converter; for the output coil
all that was handy was the 3-4" dia. core from a spool of factory
wire.

It worked real good, until the plastic melted. ;-)
Click to expand...
Did the plastic melt from its dissipation factor, or would the winding
have gotten hot enough to melt the plastic anyway?

Meanwhile, I am aware of dissipation factor being a factor in
secondaries for solid state Tesla coils. This involves electric field of
a few or several kilovolts per centimeter and coil former having volume of
at least 10's usually hundreds of cubic centimeters. Part of making
things better is making the former thinner. And usually, the ill effect I
run into is more dissipation affecting gain of the resonant system than
producing unbearable heat - power input appears to me to be whatever I put
in, and most of it becomes heat in the secondary regardless of its Q -
better Q means higher output voltage for a given set of coil and wire
dimensions and power input. I merely adjust primary turns count to
maximize delivery to the secondary, as indicated by spark length, short of
primary current becoming excessive for the driving circuit.
Sometimes the limiting factor is impedance of the driving circuit,
combined with resistance of the primary (often a bit of another matter at
a couple hundred or a few hundred KHz), especially when I use one easier
Tesla coil driving circuit limited to lower supply voltages not much over
12 volts.

Someone said that a thin cardboard tube soaked in beeswax (presumably at
a temperature thoroughly driving moisture away) works well. I seem to
think that polyethylene or polypropylene at minimum thickness necessary
for the necessary structural strength does well. I have found cardboard
tubes that carpet comes rolled on to be poor in this area, in part from
volume of material, and in part from moisture content in the material.

- Don Klipstein (don@misty.com)
 
"John Larkin" <jjlarkin@highNOTlandTHIStechnologyPART.com> wrote in message
news:i73h655jeaabgipt9ucvkldjm7ticvirse@4ax.com...
That's a horrible circuit. Too many conflicting parameters depend on
the value of R1. A proper blocking oscillator uses an RC time constant
to set the rep rate, and a separate resistor to limit the base
current.

ftp://jjlarkin.lmi.net/BlockOsc.JPG
Click to expand...
I don't think it's such a horrible circuit, but I thought I would run a
simulation on yours for comparison. I added a Schottky diode from emitter
to base of Q1 and I used 5k for R1, 1k for R2, 10 nF for C1, and a dual 100
uH choke for the magnetics, with a 2N3904. My results:

Vin Iout Freq Eff
4V 71mA 55kHz 94% eff
3V 42mA 60kHz 92% eff
2V 19mA 55kHz 88% eff

Then I added a Schottky and a 1 uF filter for the LEDs:

Vin Iout Freq Eff
4V 79mA 55kHz 90% eff
3V 47mA 60kHz 89% eff
2V 22mA 65kHz 85% eff

So I actually built a deadbug, and these are the results:

Vin Iin Vout Iout Eff
4.0V 137mA 9.55V 51mA 88% eff
3.0V 105mA 8.27V 33mA 86% eff
2.5V 100mA 7.87V 27mA 87% eff
1.6V 65mA 6.58V 12mA 79% eff
0.9V 36mA 5.67V 4mA 71% eff

I'd say that's pretty good. I used a current limited supply that saved me
when I had a wiring error, but otherwise I just wired it up and turned it
on. I used two jumbo white LEDs and they still give usable light at about
0.75 VDC input. The output varies greatly with input voltage, but it may
even be better to have the current drop off as the battery dies to give a
visual indication and also extend life as long as possible.

It seems the biggest unknown and the likeliest source of problems for the
OP has been the inductor/transformer. The coupled inductor I used is
readily available from Mouser or Digikey in a wide range of values and
sizes:
http://www.cooperbussmann.com/pdf/c1a70031-e2f0-4194-8987-a371b83bf95a.pdf

They are only about $1.76 each from Mouser:
http://www.mouser.com/Search/Refine.aspx?Keyword=drq74

Paul

The simulation:
---------------------------------------------------

Version 4
SHEET 1 880 680
WIRE -64 32 -80 32
WIRE 0 32 -64 32
WIRE 288 32 0 32
WIRE 400 32 368 32
WIRE 416 32 400 32
WIRE 544 32 416 32
WIRE 0 64 0 32
WIRE 288 64 288 32
WIRE 368 64 368 32
WIRE 416 64 416 32
WIRE -80 144 -80 32
WIRE 544 144 544 32
WIRE 288 160 288 144
WIRE 368 160 368 128
WIRE 368 160 288 160
WIRE 416 160 416 128
WIRE 0 208 0 144
WIRE 16 208 0 208
WIRE 112 208 96 208
WIRE 208 208 192 208
WIRE 224 208 208 208
WIRE 0 240 0 208
WIRE 208 256 208 208
WIRE 416 256 416 224
WIRE -80 352 -80 224
WIRE 0 352 0 304
WIRE 0 352 -80 352
WIRE 208 352 208 320
WIRE 208 352 0 352
WIRE 288 352 288 256
WIRE 288 352 208 352
WIRE 368 352 288 352
WIRE 416 352 416 320
WIRE 416 352 368 352
WIRE 544 352 544 208
WIRE 544 352 416 352
WIRE 368 384 368 352
FLAG 368 384 0
FLAG 400 32 out
FLAG -64 32 in
SYMBOL npn 224 160 R0
SYMATTR InstName Q1
SYMATTR Value 2N3904
SYMBOL res -16 48 R0
SYMATTR InstName R1
SYMATTR Value 5k
SYMBOL cap -16 240 R0
SYMATTR InstName C1
SYMATTR Value 10n
SYMBOL ind2 304 160 R180
WINDOW 0 36 80 Left 0
WINDOW 3 36 40 Left 0
SYMATTR InstName L1
SYMATTR Value 100ľ
SYMATTR Type ind
SYMBOL ind2 96 224 R270
WINDOW 0 32 56 VTop 0
WINDOW 3 5 56 VBottom 0
SYMATTR InstName L2
SYMATTR Value 100ľ
SYMATTR Type ind
SYMBOL LED 400 160 R0
SYMATTR InstName D1
SYMATTR Value AOT-2015
SYMATTR Description Diode
SYMATTR Type diode
SYMBOL LED 400 256 R0
SYMATTR InstName D2
SYMATTR Value AOT-2015
SYMATTR Description Diode
SYMATTR Type diode
SYMBOL LED 400 64 R0
SYMATTR InstName D3
SYMATTR Value AOT-2015
SYMATTR Description Diode
SYMATTR Type diode
SYMBOL voltage -80 128 R0
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V1
SYMATTR Value 4
SYMBOL res 0 224 R270
WINDOW 0 32 56 VTop 0
WINDOW 3 0 56 VBottom 0
SYMATTR InstName R2
SYMATTR Value 1k
SYMBOL schottky 224 320 R180
WINDOW 0 24 72 Left 0
WINDOW 3 24 0 Left 0
SYMATTR InstName D4
SYMATTR Value 1N5818
SYMATTR Description Diode
SYMATTR Type diode
SYMBOL schottky 384 128 R180
WINDOW 0 32 68 Left 0
WINDOW 3 24 0 Left 0
SYMATTR InstName D5
SYMATTR Value 1N5818
SYMATTR Description Diode
SYMATTR Type diode
SYMBOL cap 528 144 R0
SYMATTR InstName C2
SYMATTR Value 1ľ
TEXT 144 96 Left 0 !K1 L1 L2 1
TEXT -114 376 Left 0 !.tran 10m
TEXT -336 112 Left 0 ;4V 79mA 55 kHz 90%
TEXT -336 136 Left 0 ;3V 47mA 60 kHz 89%
TEXT -336 160 Left 0 ;2V 22mA 65 kHz 85%
 
On Aug 2, 7:20 am, greg <g...@cosc.canterbury.ac.nz> wrote:
No, anything non-metallic and non-conductive --
wood, plastic, cardboard, etc. -- should make
very little difference.
Click to expand...
Ok I got a free half-hour so I made an air-core
with a piece of plastic pipe, here's a pic:
http://www.artlum.com/jt/aircore.jpg

It's got about a 4:1 ratio on the windings ... and
it works! I even got 20mA LED current out of it.

I didn't measure efficiency - the frequency is way
too high so the transistor is heating up. I guess
I need a lot more turns on the inductor or a different
size/shape or something. I'll leave that part up to the
theorists.

I tried two batteries and I found that brightness keeps
on increasing as R1 goes down to zero. The LEDs
were still lit when R1 was just a couple of ohms.
 
On Aug 3, 2:52 am, "Paul E. Schoen" <p...@peschoen.com> wrote:
If you have installed LTspice then you should try their jig for LT1932
which is an LED driver that works down to 1.5 VDC and has built-in current
regulation. It runs at 1 MHz so the inductor can be tiny, and there are no
big spikes in the LED current as there are on the JouleThief without a
capacitor.
Click to expand...
At the moment I'm looking at the LM3914 chip to do this
- it can do 10 LEDs, needs no external inductor (in fact
pretty much zero external components), is easy to get from
eBay, etc.

I ordered three of them about a week ago, should be here
any day now...

The joule thief is a cheap/fun way to to light up an LED from
a battery but it turns out that doing five or six LEDs with
randomly scavenged parts isn't going to work out too well.
Doing it with specially purchased parts would make it about
as expensive as (eg.) the LM3914 so it hardly seems worth it.
 
On Aug 4, 8:52 am, "Paul E. Schoen" <p...@peschoen.com> wrote:
It seems the biggest unknown and the likeliest source of problems for the
OP has been the inductor/transformer.
Click to expand...
That, and any kind of clue about electronics. I know Ohms Law
from physics class at school and I remember what a transistor
is like a 'tap' and a capacitor acts like a little battery but that's
about it.
 
On Tue, 04 Aug 2009 06:52:48 GMT, "Paul E. Schoen" <paul@peschoen.com>
wrote:

"John Larkin" <jjlarkin@highNOTlandTHIStechnologyPART.com> wrote in message
news:i73h655jeaabgipt9ucvkldjm7ticvirse@4ax.com...

That's a horrible circuit. Too many conflicting parameters depend on
the value of R1. A proper blocking oscillator uses an RC time constant
to set the rep rate, and a separate resistor to limit the base
current.

ftp://jjlarkin.lmi.net/BlockOsc.JPG

I don't think it's such a horrible circuit, but I thought I would run a
simulation on yours for comparison. I added a Schottky diode from emitter
to base of Q1 and I used 5k for R1, 1k for R2, 10 nF for C1, and a dual 100
uH choke for the magnetics, with a 2N3904. My results:

Vin Iout Freq Eff
4V 71mA 55kHz 94% eff
3V 42mA 60kHz 92% eff
2V 19mA 55kHz 88% eff

Then I added a Schottky and a 1 uF filter for the LEDs:

Vin Iout Freq Eff
4V 79mA 55kHz 90% eff
3V 47mA 60kHz 89% eff
2V 22mA 65kHz 85% eff

So I actually built a deadbug, and these are the results:

Vin Iin Vout Iout Eff
4.0V 137mA 9.55V 51mA 88% eff
3.0V 105mA 8.27V 33mA 86% eff
2.5V 100mA 7.87V 27mA 87% eff
1.6V 65mA 6.58V 12mA 79% eff
0.9V 36mA 5.67V 4mA 71% eff

I'd say that's pretty good. I used a current limited supply that saved me
when I had a wiring error, but otherwise I just wired it up and turned it
on. I used two jumbo white LEDs and they still give usable light at about
0.75 VDC input. The output varies greatly with input voltage, but it may
even be better to have the current drop off as the battery dies to give a
visual indication and also extend life as long as possible.

It seems the biggest unknown and the likeliest source of problems for the
OP has been the inductor/transformer. The coupled inductor I used is
readily available from Mouser or Digikey in a wide range of values and
sizes:
http://www.cooperbussmann.com/pdf/c1a70031-e2f0-4194-8987-a371b83bf95a.pdf

They are only about $1.76 each from Mouser:
http://www.mouser.com/Search/Refine.aspx?Keyword=drq74

Paul
Click to expand...
It would be better if the transformer steps down into the base and you
disappear the Schottky. A lot of energy is lost putting a bunch of
voltage across the series base resistor, and the schottky adds
dissipation during the off period.

John








The simulation:
---------------------------------------------------

Version 4
SHEET 1 880 680
WIRE -64 32 -80 32
WIRE 0 32 -64 32
WIRE 288 32 0 32
WIRE 400 32 368 32
WIRE 416 32 400 32
WIRE 544 32 416 32
WIRE 0 64 0 32
WIRE 288 64 288 32
WIRE 368 64 368 32
WIRE 416 64 416 32
WIRE -80 144 -80 32
WIRE 544 144 544 32
WIRE 288 160 288 144
WIRE 368 160 368 128
WIRE 368 160 288 160
WIRE 416 160 416 128
WIRE 0 208 0 144
WIRE 16 208 0 208
WIRE 112 208 96 208
WIRE 208 208 192 208
WIRE 224 208 208 208
WIRE 0 240 0 208
WIRE 208 256 208 208
WIRE 416 256 416 224
WIRE -80 352 -80 224
WIRE 0 352 0 304
WIRE 0 352 -80 352
WIRE 208 352 208 320
WIRE 208 352 0 352
WIRE 288 352 288 256
WIRE 288 352 208 352
WIRE 368 352 288 352
WIRE 416 352 416 320
WIRE 416 352 368 352
WIRE 544 352 544 208
WIRE 544 352 416 352
WIRE 368 384 368 352
FLAG 368 384 0
FLAG 400 32 out
FLAG -64 32 in
SYMBOL npn 224 160 R0
SYMATTR InstName Q1
SYMATTR Value 2N3904
SYMBOL res -16 48 R0
SYMATTR InstName R1
SYMATTR Value 5k
SYMBOL cap -16 240 R0
SYMATTR InstName C1
SYMATTR Value 10n
SYMBOL ind2 304 160 R180
WINDOW 0 36 80 Left 0
WINDOW 3 36 40 Left 0
SYMATTR InstName L1
SYMATTR Value 100ľ
SYMATTR Type ind
SYMBOL ind2 96 224 R270
WINDOW 0 32 56 VTop 0
WINDOW 3 5 56 VBottom 0
SYMATTR InstName L2
SYMATTR Value 100ľ
SYMATTR Type ind
SYMBOL LED 400 160 R0
SYMATTR InstName D1
SYMATTR Value AOT-2015
SYMATTR Description Diode
SYMATTR Type diode
SYMBOL LED 400 256 R0
SYMATTR InstName D2
SYMATTR Value AOT-2015
SYMATTR Description Diode
SYMATTR Type diode
SYMBOL LED 400 64 R0
SYMATTR InstName D3
SYMATTR Value AOT-2015
SYMATTR Description Diode
SYMATTR Type diode
SYMBOL voltage -80 128 R0
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V1
SYMATTR Value 4
SYMBOL res 0 224 R270
WINDOW 0 32 56 VTop 0
WINDOW 3 0 56 VBottom 0
SYMATTR InstName R2
SYMATTR Value 1k
SYMBOL schottky 224 320 R180
WINDOW 0 24 72 Left 0
WINDOW 3 24 0 Left 0
SYMATTR InstName D4
SYMATTR Value 1N5818
SYMATTR Description Diode
SYMATTR Type diode
SYMBOL schottky 384 128 R180
WINDOW 0 32 68 Left 0
WINDOW 3 24 0 Left 0
SYMATTR InstName D5
SYMATTR Value 1N5818
SYMATTR Description Diode
SYMATTR Type diode
SYMBOL cap 528 144 R0
SYMATTR InstName C2
SYMATTR Value 1ľ
TEXT 144 96 Left 0 !K1 L1 L2 1
TEXT -114 376 Left 0 !.tran 10m
TEXT -336 112 Left 0 ;4V 79mA 55 kHz 90%
TEXT -336 136 Left 0 ;3V 47mA 60 kHz 89%
TEXT -336 160 Left 0 ;2V 22mA 65 kHz 85%
Click to expand...
 
"fungus" <openglMYSOCKS@artlum.com> wrote in message
news:1b091b3f-3895-4567-8cef-af0415da8aee@r2g2000yqm.googlegroups.com...
On Aug 4, 12:27 pm, fungus <openglMYSO...@artlum.com> wrote:

Finally ... I also ordered some little electret microphones
and they arrived in the same post. I managed to connect
one of them to the sense pin of the chip and got the LEDs
to respond to sound. I need to figure out how to
set the sensitivity by adjusting the reference voltages on
the chip but this could be megacool if I can get some of
the LEDs to respond to the drums in the processions.
Click to expand...
Plenty of info on audio level indicators
Here is one
http://www.electronic-circuits-diagrams.com/audioimages/audiockt14.shtml

More here
http://www.discovercircuits.com/A/au-tone.htm

Also look for audio VU meter circuits.
 
"John Larkin" <jjlarkin@highNOTlandTHIStechnologyPART.com> wrote in message
news:37gg7516ne85fi7gpad9cdmh7fncitm3ib@4ax.com...
It would be better if the transformer steps down into the base and you
disappear the Schottky. A lot of energy is lost putting a bunch of
voltage across the series base resistor, and the schottky adds
dissipation during the off period.
Click to expand...
Yes, without the Schottky the simulation shows 95% efficiency compared to
92%, at 3 VDC input, but with 30 mA output compared to 42 mA. But the base
voltage drops to -8 volts. If the BE junction breaks down the current is
limited by R2 so it is probably OK. This depends largely on the load
voltage, so more white LEDs in series will need higher voltage and thus the
voltage on the base will be higher. But for one or two LEDs and 1.5 to 3
volts input this is not a problem.

Paul
 
On Aug 4, 12:27 pm, fungus <openglMYSO...@artlum.com> wrote:
I ordered three of them about a week ago, should be here
any day now...
Click to expand...
They arrived!

I got one to light up a bunch of LEDs using only the chip
and one external resistor (which adjusts the LED current).

Next I made a simple voltage divider on the input pin with
a resistor and pot. Turning the pot left/right lights up one
of the LEDs in sequence - cool. It also switches instantly
between LEDs as you turn (no in-between brightness)
which looks good.

Finally ... I also ordered some little electret microphones
and they arrived in the same post. I managed to connect
one of them to the sense pin of the chip and got the LEDs
to respond to sound. I need to figure out how to
set the sensitivity by adjusting the reference voltages on
the chip but this could be megacool if I can get some of
the LEDs to respond to the drums in the processions.
 
On Tue, 04 Aug 2009 01:14:46 +0000, Don Klipstein wrote:

In article <pan.2009.08.04.00.31.08.757860@example.net>, Rich Grise wrote:
On Sun, 02 Aug 2009 18:15:08 -0500, John Fields wrote:
On Sun, 02 Aug 2009 17:20:07 +1200, greg <greg@cosc.canterbury.ac.nz
fungus wrote:

I assume there has to be actual air there, not a stick, so whatever
I wind it onto has to be removed, right?

No, anything non-metallic and non-conductive --
wood, plastic, cardboard, etc. -- should make
very little difference.

IME that's not true.

A couple of hundred years ago (it seems) I built a 2kW CW ultrasonic
system where I used a piece of PVC pipe as a former to wind the loading
coil for the transducer and when we fired it up and tuned the system to
resonance, the pipe melted.

"Dissipation factor", I later learned, was what had bitten me on the
ass, and I solved the problem by cannibalizing the ceramic (steatite)
core of an ARC5's loading coil and winding it to get the inductance we
needed for resonance at 40kHz.

I once tried to build a simple buck converter; for the output coil
all that was handy was the 3-4" dia. core from a spool of factory
wire.

It worked real good, until the plastic melted. ;-)

Did the plastic melt from its dissipation factor, or would the winding
have gotten hot enough to melt the plastic anyway?
Click to expand...
OK, I confess - the winding got hot. ;-)

Thanks,
Rich
 
"bw" <bwegher@hotmail.com> wrote in message
news:h59trs$gja$1@news.eternal-september.org...
"fungus" <openglMYSOCKS@artlum.com> wrote in message
news:1b091b3f-3895-4567-8cef-af0415da8aee@r2g2000yqm.googlegroups.com...
On Aug 4, 12:27 pm, fungus <openglMYSO...@artlum.com> wrote:

Finally ... I also ordered some little electret microphones
and they arrived in the same post. I managed to connect
one of them to the sense pin of the chip and got the LEDs
to respond to sound. I need to figure out how to
set the sensitivity by adjusting the reference voltages on
the chip but this could be megacool if I can get some of
the LEDs to respond to the drums in the processions.

Plenty of info on audio level indicators
Here is one
http://www.electronic-circuits-diagrams.com/audioimages/audiockt14.shtml

More here
http://www.discovercircuits.com/A/au-tone.htm

Also look for audio VU meter circuits.
Click to expand...
Something else that is cool is a "color organ". I made one about 40 years
ago that connected to my 8 track car tape player and flashed three
different colors to three ranges of frequency. I think I used red for low
notes, yellow for mid range, and blue for high frequency. These were
incandescent lamps. I still have the beast somewhere, but I have not used
it for a long time. Here are some links:

http://www.discovercircuits.com/C/color-org.htm

Paul
 
On Aug 5, 12:02 am, "Paul E. Schoen" <p...@peschoen.com> wrote:
Something else that is cool is a "color organ". I made one about 40 years
ago that connected to my 8 track car tape player and flashed three
different colors to three ranges of frequency.
Click to expand...
Response to different frequencies would be very nice...
 
On Aug 4, 7:37 pm, fungus <openglMYSO...@artlum.com> wrote:
I got one to light up a bunch of LEDs using only the chip
and one external resistor (which adjusts the LED current).
Click to expand...
I'm just running a set of batteries flat through one to
see how it goes.

The bad new is ... I think it might need four batteries to
keep a full 20mA going though the 3.3V LEDs.
 
Just another interesting note on the subject of not having to pay for
postage costs getting isolated electronic parts for the joule thief. I
just opened up a BPCE13T/8 compact fluorescent bulb's base. (It was
dead.) Here's a web page about it:

http://www.onebillionbulbs.com/cfl-bulbs/BPCE13T%2F8-Spiral/1288/US

And inside I found:

(1) 10uF, 200V Nichicon elecrolytic capacitor
(5) 1N4007 diodes
(2) BJTs (I would have guessed MOSFETs before looking at the board,
but I saw an E C B silkscreeded on the board, so I figure
that means BJTs.)
(1) Micrometals T50-6 powdered iron toroid (.5" outer dia) with a
relative permeability of 8.5 (so they say.)

Just to name some of them. That toroid would require about 100 turns
on the collector winding to get up to 40uH. With an inner diameter of
..303", 100 turns would require fine wire (32 gauge or smaller, I
think.) But it's parts!! (There's also a pretty hefty inductor there
with lots of magnet wire that could be used with the toroid. The wire
looks like #32 to the eye, but I haven't pulled out a length of it to
measure with the micrometer.)

Okay. Here's a cobbled-up schematic on it:

http://www.repairfaq.org/sam/cflamp3.pdf

I guess they are BJTs. So it looks like most of what's needed is
right inside there.

A page on the T50-6 is at
http://toroids.info/T50-6.php

Jon

P.S. Those CFLs fail a lot so I have a ready source of parts until I
exhaust the package of them I bought.
 
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