Looking for a Low Cost On Delay Timer

G

Guv Bob

Guest
Names can be confusing, so here's what I'm doing....

http://img43.imageshack.us/img43/7434/wvm.gif

When 12VDC is applied to the input, I need a 12VDC output for 5 seconds. Then output will go back off and stay off until the input goes to zero. Then cycle starts again.

Current for both legs is in the 10-50ma range.

A simple on-delay timer would work but I'm having trouble finding one with NC contacts. Tons of stuff $100+, but for this application, it has to be under $20.
 
On Tue, 20 Aug 2013 14:12:28 -0700, "Guv Bob"
<guvbob2003@yahooooooooooooooo.com> wrote:

Names can be confusing, so here's what I'm doing....

http://img43.imageshack.us/img43/7434/wvm.gif

When 12VDC is applied to the input, I need a 12VDC output for 5 seconds. Then output will go back off and stay off until the input goes to zero. Then cycle starts again.

Current for both legs is in the 10-50ma range.

A simple on-delay timer would work but I'm having trouble finding one with NC contacts. Tons of stuff $100+, but for this application, it has to be under $20.
Click to expand...

---
For way under $20, this'll work, and if you need NC contacts, all
you'll have to do is put either a solid state relay or a mechanical
relay with a catch diode across the LED.

Version 4
SHEET 1 880 680
WIRE 0 -48 -128 -48
WIRE 160 -48 0 -48
WIRE 256 -48 160 -48
WIRE 352 -48 256 -48
WIRE 400 -48 352 -48
WIRE 528 -48 480 -48
WIRE 528 -16 528 -48
WIRE 0 0 0 -48
WIRE 160 0 160 -48
WIRE 352 0 352 -48
WIRE 528 80 528 48
WIRE 256 96 256 -48
WIRE 0 112 0 80
WIRE 224 112 0 112
WIRE -128 128 -128 -48
WIRE -96 128 -128 128
WIRE 0 128 0 112
WIRE 0 128 -32 128
WIRE 352 128 352 80
WIRE 352 128 288 128
WIRE 464 128 352 128
WIRE 160 144 160 80
WIRE 224 144 160 144
WIRE -128 176 -128 128
WIRE 0 176 0 128
WIRE 160 176 160 144
WIRE 528 256 528 176
WIRE -128 288 -128 256
WIRE 0 288 0 240
WIRE 0 288 -128 288
WIRE 160 288 160 256
WIRE 160 288 0 288
WIRE 256 288 256 160
WIRE 256 288 160 288
WIRE -128 320 -128 288
FLAG 528 256 0
FLAG -128 320 0
SYMBOL Comparators\\LT1017 256 128 R0
WINDOW 0 27 24 Left 2
WINDOW 3 12 52 Left 2
SYMATTR InstName U1
SYMBOL npn 464 80 R0
SYMATTR InstName Q1
SYMATTR Value 2N3904
SYMBOL res 336 -16 R0
SYMATTR InstName R1
SYMATTR Value 10k
SYMBOL res 496 -64 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R2
SYMATTR Value 680
SYMBOL LED 512 -16 R0
SYMATTR InstName D3
SYMATTR Value NSCW100
SYMBOL res 144 -16 R0
SYMATTR InstName R3
SYMATTR Value 100k
SYMBOL res 144 160 R0
SYMATTR InstName R4
SYMATTR Value 150k
SYMBOL cap -16 176 R0
SYMATTR InstName C1
SYMATTR Value 0.47ľ
SYMBOL res -16 -16 R0
SYMATTR InstName R5
SYMATTR Value 10meg
SYMBOL voltage -128 160 R0
WINDOW 3 24 96 Invisible 2
WINDOW 123 0 0 Left 2
WINDOW 39 0 0 Left 2
SYMATTR InstName V1
SYMATTR Value PULSE(0 12 1 10ms 10ms 5s 10s)
SYMBOL diode -32 112 R90
WINDOW 0 -38 31 VBottom 2
WINDOW 3 -33 37 VTop 2
SYMATTR InstName D2
SYMATTR Value 1N4148
TEXT -162 344 Left 2 !.tran 20 startup


--
JF
 
"John Fields" <jfields@austininstruments.com> wrote in message news:v9t719dati1na5hk704o9rfacest5hr8lc@4ax.com...
On Tue, 20 Aug 2013 14:12:28 -0700, "Guv Bob"
guvbob2003@yahooooooooooooooo.com> wrote:

Names can be confusing, so here's what I'm doing....

http://img43.imageshack.us/img43/7434/wvm.gif

When 12VDC is applied to the input, I need a 12VDC output for 5 seconds. Then output will go back off and stay off until the input goes to zero. Then cycle starts again.

Current for both legs is in the 10-50ma range.

A simple on-delay timer would work but I'm having trouble finding one with NC contacts. Tons of stuff $100+, but for this application, it has to be under $20.

---
For way under $20, this'll work, and if you need NC contacts, all
you'll have to do is put either a solid state relay or a mechanical
relay with a catch diode across the LED.
Click to expand...

Thanks John, I'm not following you. Can you sketch the circuit?

Version 4
SHEET 1 880 680
WIRE 0 -48 -128 -48
WIRE 160 -48 0 -48
WIRE 256 -48 160 -48
WIRE 352 -48 256 -48
WIRE 400 -48 352 -48
WIRE 528 -48 480 -48
WIRE 528 -16 528 -48
WIRE 0 0 0 -48
WIRE 160 0 160 -48
WIRE 352 0 352 -48
WIRE 528 80 528 48
WIRE 256 96 256 -48
WIRE 0 112 0 80
WIRE 224 112 0 112
WIRE -128 128 -128 -48
WIRE -96 128 -128 128
WIRE 0 128 0 112
WIRE 0 128 -32 128
WIRE 352 128 352 80
WIRE 352 128 288 128
WIRE 464 128 352 128
WIRE 160 144 160 80
WIRE 224 144 160 144
WIRE -128 176 -128 128
WIRE 0 176 0 128
WIRE 160 176 160 144
WIRE 528 256 528 176
WIRE -128 288 -128 256
WIRE 0 288 0 240
WIRE 0 288 -128 288
WIRE 160 288 160 256
WIRE 160 288 0 288
WIRE 256 288 256 160
WIRE 256 288 160 288
WIRE -128 320 -128 288
FLAG 528 256 0
FLAG -128 320 0
SYMBOL Comparators\\LT1017 256 128 R0
WINDOW 0 27 24 Left 2
WINDOW 3 12 52 Left 2
SYMATTR InstName U1
SYMBOL npn 464 80 R0
SYMATTR InstName Q1
SYMATTR Value 2N3904
SYMBOL res 336 -16 R0
SYMATTR InstName R1
SYMATTR Value 10k
SYMBOL res 496 -64 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R2
SYMATTR Value 680
SYMBOL LED 512 -16 R0
SYMATTR InstName D3
SYMATTR Value NSCW100
SYMBOL res 144 -16 R0
SYMATTR InstName R3
SYMATTR Value 100k
SYMBOL res 144 160 R0
SYMATTR InstName R4
SYMATTR Value 150k
SYMBOL cap -16 176 R0
SYMATTR InstName C1
SYMATTR Value 0.47ľ
SYMBOL res -16 -16 R0
SYMATTR InstName R5
SYMATTR Value 10meg
SYMBOL voltage -128 160 R0
WINDOW 3 24 96 Invisible 2
WINDOW 123 0 0 Left 2
WINDOW 39 0 0 Left 2
SYMATTR InstName V1
SYMATTR Value PULSE(0 12 1 10ms 10ms 5s 10s)
SYMBOL diode -32 112 R90
WINDOW 0 -38 31 VBottom 2
WINDOW 3 -33 37 VTop 2
SYMATTR InstName D2
SYMATTR Value 1N4148
TEXT -162 344 Left 2 !.tran 20 startup


--
JF
Click to expand...
 
On Wed, 21 Aug 2013 10:30:46 -0700, "Guv Bob"
<guvbob2003@yahooooooooooooooo.com> wrote:

"John Fields" <jfields@austininstruments.com> wrote in message news:v9t719dati1na5hk704o9rfacest5hr8lc@4ax.com...
On Tue, 20 Aug 2013 14:12:28 -0700, "Guv Bob"
guvbob2003@yahooooooooooooooo.com> wrote:

Names can be confusing, so here's what I'm doing....

http://img43.imageshack.us/img43/7434/wvm.gif

When 12VDC is applied to the input, I need a 12VDC output for 5 seconds. Then output will go back off and stay off until the input goes to zero. Then cycle starts again.

Current for both legs is in the 10-50ma range.

A simple on-delay timer would work but I'm having trouble finding one with NC contacts. Tons of stuff $100+, but for this application, it has to be under $20.

---
For way under $20, this'll work, and if you need NC contacts, all
you'll have to do is put either a solid state relay or a mechanical
relay with a catch diode across the LED.


Thanks John, I'm not following you. Can you sketch the circuit?
Click to expand...

---
Sure.

View with a fixed-pitch font like Courier New:


GND->\ <- +12
O-----+----+---+---+------+-----+-------+ +--------NO
| | | | | | | | | O--C
| | | | | [680] |K | O-> \<--NC
|K | | | | | [1N4148] [COIL]- - - -\
[1N4148][7M5][100K]| [10K] [LED] | |
| |Rt | | | |K | |
| | | | | +-----+-------+
| | | | | |
+-----+----|--|-\ | C
| | | >-+----B 2N3904
|Ct +--|+/U1 E Q1
[1ľF] | | |
| [100K]| |
| | | |
GND>--------+----+---+----------+

U1 is any comparator with an input resistance which won't swamp Rt,
and an open-collector output (or an output with a weak pullup to Vcc)
which can sink a few mA without letting Q1 go out of saturation.

So, what's your application?

--
JF
 
John Fields" <jfields@austininstruments.com> wrote in message news:5iba19tar9kb0tdl0tcurqkll3t8655v5v@4ax.com...
On Wed, 21 Aug 2013 10:30:46 -0700, "Guv Bob"
guvbob2003@yahooooooooooooooo.com> wrote:

"John Fields" <jfields@austininstruments.com> wrote in message news:v9t719dati1na5hk704o9rfacest5hr8lc@4ax.com...
On Tue, 20 Aug 2013 14:12:28 -0700, "Guv Bob"
guvbob2003@yahooooooooooooooo.com> wrote:

Names can be confusing, so here's what I'm doing....

http://img43.imageshack.us/img43/7434/wvm.gif

When 12VDC is applied to the input, I need a 12VDC output for 5 seconds. Then output will go back off and stay off until the input goes to zero. Then cycle starts again.

Current for both legs is in the 10-50ma range.

A simple on-delay timer would work but I'm having trouble finding one with NC contacts. Tons of stuff $100+, but for this application, it has to be under $20.

---
For way under $20, this'll work, and if you need NC contacts, all
you'll have to do is put either a solid state relay or a mechanical
relay with a catch diode across the LED.


Thanks John, I'm not following you. Can you sketch the circuit?

---
Sure.

View with a fixed-pitch font like Courier New:


GND->\ <- +12
O-----+----+---+---+------+-----+-------+ +--------NO
| | | | | | | | | O--C
| | | | | [680] |K | O-> \<--NC
|K | | | | | [1N4148] [COIL]- - - -\
[1N4148][7M5][100K]| [10K] [LED] | |
| |Rt | | | |K | |
| | | | | +-----+-------+
| | | | | |
+-----+----|--|-\ | C
| | | >-+----B 2N3904
|Ct +--|+/U1 E Q1
[1ľF] | | |
| [100K]| |
| | | |
GND>--------+----+---+----------+

U1 is any comparator with an input resistance which won't swamp Rt,
and an open-collector output (or an output with a weak pullup to Vcc)
which can sink a few mA without letting Q1 go out of saturation.

So, what's your application?

--
JF
Click to expand...

Thanks again! Would this work?

NTE955M Timer, (555 Type), 200 mA Iout, CMOS 8 DIP 1.20
http://www.alliedelec.com/search/productdetail.aspx?sku=70215850
 
On Wed, 21 Aug 2013 16:46:13 -0700, "Guv Bob"
<guvbob2003@yahooooooooooooooo.com> wrote:

John Fields" <jfields@austininstruments.com> wrote in message news:5iba19tar9kb0tdl0tcurqkll3t8655v5v@4ax.com...
On Wed, 21 Aug 2013 10:30:46 -0700, "Guv Bob"
guvbob2003@yahooooooooooooooo.com> wrote:

"John Fields" <jfields@austininstruments.com> wrote in message news:v9t719dati1na5hk704o9rfacest5hr8lc@4ax.com...
On Tue, 20 Aug 2013 14:12:28 -0700, "Guv Bob"
guvbob2003@yahooooooooooooooo.com> wrote:

Names can be confusing, so here's what I'm doing....

http://img43.imageshack.us/img43/7434/wvm.gif

When 12VDC is applied to the input, I need a 12VDC output for 5 seconds. Then output will go back off and stay off until the input goes to zero. Then cycle starts again.

Current for both legs is in the 10-50ma range.

A simple on-delay timer would work but I'm having trouble finding one with NC contacts. Tons of stuff $100+, but for this application, it has to be under $20.

---
For way under $20, this'll work, and if you need NC contacts, all
you'll have to do is put either a solid state relay or a mechanical
relay with a catch diode across the LED.


Thanks John, I'm not following you. Can you sketch the circuit?

---
Sure.

View with a fixed-pitch font like Courier New:


GND->\ <- +12
O-----+----+---+---+------+-----+-------+ +--------NO
| | | | | | | | | O--C
| | | | | [680] |K | O-> \<--NC
|K | | | | | [1N4148] [COIL]- - - -\
[1N4148][7M5][100K]| [10K] [LED] | |
| |Rt | | | |K | |
| | | | | +-----+-------+
| | | | | |
+-----+----|--|-\ | C
| | | >-+----B 2N3904
|Ct +--|+/U1 E Q1
[1ľF] | | |
| [100K]| |
| | | |
GND>--------+----+---+----------+

U1 is any comparator with an input resistance which won't swamp Rt,
and an open-collector output (or an output with a weak pullup to Vcc)
which can sink a few mA without letting Q1 go out of saturation.

So, what's your application?

--
JF


Thanks again! Would this work?

NTE955M Timer, (555 Type), 200 mA Iout, CMOS 8 DIP 1.20
http://www.alliedelec.com/search/productdetail.aspx?sku=70215850
Click to expand...

---
If you can work out how to trigger it on the rising edge you said you
wanted your timer to, it might, but $1.20 is a little high for a 555.

--
JF
 
"George Herold" <gherold@teachspin.com> wrote in message news:5979ddc6-9c48-410d-ac4e-249c8421812e@googlegroups.com...
On Wednesday, August 21, 2013 7:46:13 PM UTC-4, Guv Bob wrote:
John Fields" <jfields@austininstruments.com> wrote in message news:5iba19tar9kb0tdl0tcurqkll3t8655v5v@4ax.com...

On Wed, 21 Aug 2013 10:30:46 -0700, "Guv Bob"

guvbob2003@yahooooooooooooooo.com> wrote:



"John Fields" <jfields@austininstruments.com> wrote in message news:v9t719dati1na5hk704o9rfacest5hr8lc@4ax.com...

On Tue, 20 Aug 2013 14:12:28 -0700, "Guv Bob"

guvbob2003@yahooooooooooooooo.com> wrote:



Names can be confusing, so here's what I'm doing....



http://img43.imageshack.us/img43/7434/wvm.gif



When 12VDC is applied to the input, I need a 12VDC output for 5 seconds. Then output will go back off and stay off until the input goes to zero. Then cycle starts again.



Current for both legs is in the 10-50ma range.



A simple on-delay timer would work but I'm having trouble finding one with NC contacts. Tons of stuff $100+, but for this application, it has to be under $20.



---

For way under $20, this'll work, and if you need NC contacts, all

you'll have to do is put either a solid state relay or a mechanical

relay with a catch diode across the LED.





Thanks John, I'm not following you. Can you sketch the circuit?



---

Sure.



View with a fixed-pitch font like Courier New:





GND->\ <- +12

O-----+----+---+---+------+-----+-------+ +--------NO

| | | | | | | | | O--C

| | | | | [680] |K | O-> \<--NC

|K | | | | | [1N4148] [COIL]- - - -\

[1N4148][7M5][100K]| [10K] [LED] | |

| |Rt | | | |K | |

| | | | | +-----+-------+

| | | | | |

+-----+----|--|-\ | C

| | | >-+----B 2N3904

|Ct +--|+/U1 E Q1

[1ľF] | | |

| [100K]| |

| | | |

GND>--------+----+---+----------+



U1 is any comparator with an input resistance which won't swamp Rt,

and an open-collector output (or an output with a weak pullup to Vcc)

which can sink a few mA without letting Q1 go out of saturation.



So, what's your application?



--

JF





Thanks again! Would this work?



NTE955M Timer, (555 Type), 200 mA Iout, CMOS 8 DIP 1.20

http://www.alliedelec.com/search/productdetail.aspx?sku=70215850
Click to expand...

I was going to say this sounded like a perfect fit for a 555 timer.
(So what's the best RC combo to get 5 seconds from a 555?)

George H.


I used to know all that stuff by heart, but I've been swapping modules too long. This not the usual rush job, so it's a nice change to be able to spend some time on it. Now I'm off to re-learn all the RC stuff.
 
On 2013-08-21, Guv Bob <guvbob2003@yahooooooooooooooo.com> wrote:
On Tue, 20 Aug 2013 14:12:28 -0700, "Guv Bob"

http://img43.imageshack.us/img43/7434/wvm.gif

Thanks again! Would this work?

NTE955M Timer, (555 Type), 200 mA Iout, CMOS 8 DIP 1.20
http://www.alliedelec.com/search/productdetail.aspx?sku=70215850
Click to expand...

Maybe like this:

in------+-------------+
| |
| . . . .|. . . .
| . VCC(8) .
| . .
+-----+-------RES(4) OUT(3)------ out
_|_ | . 555 .
D1 A [R1] +---TH(6) DIS(7)--
'T` | | . .
+-----+---+---TR(2) CV(5)--
| . .
C1 ===== . GND(1) .
| . . . .|. . . .
| |
----+-------------+---
ground

U1 LMC555 / 7555
D1 1N914
C1 10uF
R1 470K

--
⚂⚃ 100% natural

--- news://freenews.netfront.net/ - complaints: news@netfront.net ---
 
On 22 Aug 2013 07:21:34 GMT, Jasen Betts <jasen@xnet.co.nz> wrote:

On 2013-08-21, Guv Bob <guvbob2003@yahooooooooooooooo.com> wrote:
On Tue, 20 Aug 2013 14:12:28 -0700, "Guv Bob"

http://img43.imageshack.us/img43/7434/wvm.gif

Thanks again! Would this work?

NTE955M Timer, (555 Type), 200 mA Iout, CMOS 8 DIP 1.20
http://www.alliedelec.com/search/productdetail.aspx?sku=70215850

Maybe like this:

in------+-------------+
| |
| . . . .|. . . .
| . VCC(8) .
| . .
+-----+-------RES(4) OUT(3)------ out
_|_ | . 555 .
D1 A [R1] +---TH(6) DIS(7)--
'T` | | . .
+-----+---+---TR(2) CV(5)--
| . .
C1 ===== . GND(1) .
| . . . .|. . . .
| |
----+-------------+---
ground

U1 LMC555 / 7555
D1 1N914
C1 10uF
R1 470K
Click to expand...

---
Yup! :)

--
JF
 
On Wed, 21 Aug 2013 19:08:34 -0700, "Guv Bob"
<guvbob2003@yahooooooooooooooo.com> wrote:


>I used to know all that stuff by heart, but I've been swapping modules too long. This not the usual rush job, so it's a nice change to be able to spend some time on it. Now I'm off to re-learn all the RC stuff.

---
Just for grins, the device you've described is an "OFF delay" timer.

--
JF
 
"John Fields" <jfields@austininstruments.com> wrote in message news:t3tb19dubeip5p8cc9g4uhk7idue7t2unj@4ax.com...
On Wed, 21 Aug 2013 19:08:34 -0700, "Guv Bob"
guvbob2003@yahooooooooooooooo.com> wrote:


I used to know all that stuff by heart, but I've been swapping modules too long. This not the usual rush job, so it's a nice change to be able to spend some time on it. Now I'm off to re-learn all the RC stuff.

---
Just for grins, the device you've described is an "OFF delay" timer.

--
JF
Click to expand...

That was my 2nd guess. LOL!
 
On Thu, 22 Aug 2013 06:24:12 -0500, John Fields
<jfields@austininstruments.com> wrote:

On Wed, 21 Aug 2013 19:08:34 -0700, "Guv Bob"
guvbob2003@yahooooooooooooooo.com> wrote:


I used to know all that stuff by heart, but I've been swapping modules too long. This not the usual rush job, so it's a nice change to be able to spend some time on it. Now I'm off to re-learn all the RC stuff.

---
Just for grins, the device you've described is an "OFF delay" timer.
Click to expand...

In industrial relay timer parlance, we'd call that an "interval
timer". An "off delay" timer would drop out a period of time after the
power was removed (a more rare beast since it would have two power
supplies or a big capacitor inside). An interval timer is/was just an
on delay timer with logic inversion before the relay driver, so it
pulled in immediately upon connection to the power source and drops
out after the delay.

The terms are used differently in different domains so I wouldn't
count on them being valid in any particular instance. For example,
some cretinous poltroons will refer to a recycle timer as an "interval
timer".

Best regards,
Spehro Pefhany
 
On 8/20/2013 2:12 PM, Guv Bob wrote:
Names can be confusing, so here's what I'm doing....

http://img43.imageshack.us/img43/7434/wvm.gif

When 12VDC is applied to the input, I need a 12VDC output for 5 seconds. Then output will go back off and stay off until the input goes to zero. Then cycle starts again.

Current for both legs is in the 10-50ma range.

A simple on-delay timer would work but I'm having trouble finding one with NC contacts. Tons of stuff $100+, but for this application, it has to be under $20.
Click to expand...

These used to be called "Delay Relays" and looked like a vacuum tube.
Now there are solid state models. See
<http://www.ia.omron.com/data_pdf/data_sheet/h3y_dsheet_csm92.pdf>.

You can find these on eBay, i.e.
<http://www.ebay.com/itm/H3Y2-DC-12V-5A-Delay-Timer-Time-Relay-5S-05-Seconds-w-H3Y2-Base-/330673623762>

You should be able to figure out a way to get what you need though you
may need another regular relay as a latch.

Well under $20.
 
On Wed, 21 Aug 2013 19:45:34 -0500, John Fields
<jfields@austininstruments.com> wrote:

On Wed, 21 Aug 2013 16:46:13 -0700, "Guv Bob"
guvbob2003@yahooooooooooooooo.com> wrote:

John Fields" <jfields@austininstruments.com> wrote in message news:5iba19tar9kb0tdl0tcurqkll3t8655v5v@4ax.com...
On Wed, 21 Aug 2013 10:30:46 -0700, "Guv Bob"
guvbob2003@yahooooooooooooooo.com> wrote:

"John Fields" <jfields@austininstruments.com> wrote in message news:v9t719dati1na5hk704o9rfacest5hr8lc@4ax.com...
On Tue, 20 Aug 2013 14:12:28 -0700, "Guv Bob"
guvbob2003@yahooooooooooooooo.com> wrote:

Names can be confusing, so here's what I'm doing....

http://img43.imageshack.us/img43/7434/wvm.gif

When 12VDC is applied to the input, I need a 12VDC output for 5 seconds. Then output will go back off and stay off until the input goes to zero. Then cycle starts again.

Current for both legs is in the 10-50ma range.

A simple on-delay timer would work but I'm having trouble finding one with NC contacts. Tons of stuff $100+, but for this application, it has to be under $20.

---
For way under $20, this'll work, and if you need NC contacts, all
you'll have to do is put either a solid state relay or a mechanical
relay with a catch diode across the LED.


Thanks John, I'm not following you. Can you sketch the circuit?

---
Sure.

View with a fixed-pitch font like Courier New:


GND->\ <- +12
O-----+----+---+---+------+-----+-------+ +--------NO
| | | | | | | | | O--C
| | | | | [680] |K | O-> \<--NC
|K | | | | | [1N4148] [COIL]- - - -\
[1N4148][7M5][100K]| [10K] [LED] | |
| |Rt | | | |K | |
| | | | | +-----+-------+
| | | | | |
+-----+----|--|-\ | C
| | | >-+----B 2N3904
|Ct +--|+/U1 E Q1
[1ľF] | | |
| [100K]| |
| | | |
GND>--------+----+---+----------+

U1 is any comparator with an input resistance which won't swamp Rt,
and an open-collector output (or an output with a weak pullup to Vcc)
which can sink a few mA without letting Q1 go out of saturation.

So, what's your application?

--
JF


Thanks again! Would this work?

NTE955M Timer, (555 Type), 200 mA Iout, CMOS 8 DIP 1.20
http://www.alliedelec.com/search/productdetail.aspx?sku=70215850

---
If you can work out how to trigger it on the rising edge you said you
wanted your timer to, it might, but $1.20 is a little high for a 555.
Click to expand...

Simple just use the Reset Pin..
 
On Wed, 21 Aug 2013 16:46:13 -0700, "Guv Bob"
<guvbob2003@yahooooooooooooooo.com> wrote:

John Fields" <jfields@austininstruments.com> wrote in message news:5iba19tar9kb0tdl0tcurqkll3t8655v5v@4ax.com...
On Wed, 21 Aug 2013 10:30:46 -0700, "Guv Bob"
guvbob2003@yahooooooooooooooo.com> wrote:

"John Fields" <jfields@austininstruments.com> wrote in message news:v9t719dati1na5hk704o9rfacest5hr8lc@4ax.com...
On Tue, 20 Aug 2013 14:12:28 -0700, "Guv Bob"
guvbob2003@yahooooooooooooooo.com> wrote:

Names can be confusing, so here's what I'm doing....

http://img43.imageshack.us/img43/7434/wvm.gif

When 12VDC is applied to the input, I need a 12VDC output for 5 seconds. Then output will go back off and stay off until the input goes to zero. Then cycle starts again.

Current for both legs is in the 10-50ma range.

A simple on-delay timer would work but I'm having trouble finding one with NC contacts. Tons of stuff $100+, but for this application, it has to be under $20.

---
For way under $20, this'll work, and if you need NC contacts, all
you'll have to do is put either a solid state relay or a mechanical
relay with a catch diode across the LED.


Thanks John, I'm not following you. Can you sketch the circuit?

---
Sure.

View with a fixed-pitch font like Courier New:


GND->\ <- +12
O-----+----+---+---+------+-----+-------+ +--------NO
| | | | | | | | | O--C
| | | | | [680] |K | O-> \<--NC
|K | | | | | [1N4148] [COIL]- - - -\
[1N4148][7M5][100K]| [10K] [LED] | |
| |Rt | | | |K | |
| | | | | +-----+-------+
| | | | | |
+-----+----|--|-\ | C
| | | >-+----B 2N3904
|Ct +--|+/U1 E Q1
[1ľF] | | |
| [100K]| |
| | | |
GND>--------+----+---+----------+

U1 is any comparator with an input resistance which won't swamp Rt,
and an open-collector output (or an output with a weak pullup to Vcc)
which can sink a few mA without letting Q1 go out of saturation.

So, what's your application?

--
JF


Thanks again! Would this work?

NTE955M Timer, (555 Type), 200 mA Iout, CMOS 8 DIP 1.20
http://www.alliedelec.com/search/productdetail.aspx?sku=70215850
Click to expand...

Yes that is the way I would do it I have done many many projects using a
555 Time IC..
 
"Guv Bob" <guvbob2003@yahooooooooooooooo.com> wrote in message news:1_udnQ7rBpNjRo7PnZ2dnUVZ_sidnZ2d@earthlink.com...
Names can be confusing, so here's what I'm doing....

http://img43.imageshack.us/img43/7434/wvm.gif

When 12VDC is applied to the input, I need a 12VDC output for 5 seconds. Then output will go back off and stay off until the input goes to zero. Then cycle starts again.

Current for both legs is in the 10-50ma range.

A simple on-delay timer would work but I'm having trouble finding one with NC contacts. Tons of stuff $100+, but for this application, it has to be under $20.

==
Thanks for all the tips and good info. I had wanted to put something together from components but my brain is too far behind these days. I'm going to give this a shot and hopefully I'm not picking the wrong one. It's $5 at Frys...

Velleman MK111
http://www.vellemanusa.com/downloads/0/minikits/manuals/manual_mk111.pdf
 
On a sunny day (Sun, 25 Aug 2013 23:29:54 -0700) it happened "Guv Bob"
<guvbob2003@yahooooooooooooooo.com> wrote in
<ZLSdnUtnedbva4fPnZ2dnUVZ_rKdnZ2d@earthlink.com>:

"Guv Bob" <guvbob2003@yahooooooooooooooo.com> wrote in message =
news:1_udnQ7rBpNjRo7PnZ2dnUVZ_sidnZ2d@earthlink.com...
Names can be confusing, so here's what I'm doing....

http://img43.imageshack.us/img43/7434/wvm.gif

When 12VDC is applied to the input, I need a 12VDC output for 5 seconds. =
Then output will go back off and stay off until the input goes to zero. =
Then cycle starts again.
Click to expand...

The reason I did not reply with a ciruit or whatever is
that your logic is false.

You say: 'until', that means the output goes active again.
Then you say : 'cycle starts again',
but that cycle is not the same now (starts active).

First, for yourself, work out the correct logic.
Then you already have the solution,
probably from stuff you have laying about.
 
On Sun, 25 Aug 2013 23:29:54 -0700, "Guv Bob"
<guvbob2003@yahooooooooooooooo.com> wrote:

"Guv Bob" <guvbob2003@yahooooooooooooooo.com> wrote in message news:1_udnQ7rBpNjRo7PnZ2dnUVZ_sidnZ2d@earthlink.com...
Names can be confusing, so here's what I'm doing....

http://img43.imageshack.us/img43/7434/wvm.gif

When 12VDC is applied to the input, I need a 12VDC output for 5 seconds. Then output will go back off and stay off until the input goes to zero. Then cycle starts again.

Current for both legs is in the 10-50ma range.

A simple on-delay timer would work but I'm having trouble finding one with NC contacts. Tons of stuff $100+, but for this application, it has to be under $20.

===

Thanks for all the tips and good info. I had wanted to put something together from components but my brain is too far behind these days. I'm going to give this a shot and hopefully I'm not picking the wrong one. It's $5 at Frys...

Velleman MK111
http://www.vellemanusa.com/downloads/0/minikits/manuals/manual_mk111.pdf
Click to expand...

It can be modified to do what you say you want.
 
"Spehro Pefhany" <speffSNIP@interlogDOTyou.knowwhat> wrote in message news:l20n191irlkc14q13f9on9l0tctgtihjva@4ax.com...
On Sun, 25 Aug 2013 23:29:54 -0700, "Guv Bob"
guvbob2003@yahooooooooooooooo.com> wrote:

"Guv Bob" <guvbob2003@yahooooooooooooooo.com> wrote in message news:1_udnQ7rBpNjRo7PnZ2dnUVZ_sidnZ2d@earthlink.com...
Names can be confusing, so here's what I'm doing....

http://img43.imageshack.us/img43/7434/wvm.gif

When 12VDC is applied to the input, I need a 12VDC output for 5 seconds. Then output will go back off and stay off until the input goes to zero. Then cycle starts again.

Current for both legs is in the 10-50ma range.

A simple on-delay timer would work but I'm having trouble finding one with NC contacts. Tons of stuff $100+, but for this application, it has to be under $20.

==
Thanks for all the tips and good info. I had wanted to put something together from components but my brain is too far behind these days. I'm going to give this a shot and hopefully I'm not picking the wrong one. It's $5 at Frys...

Velleman MK111
http://www.vellemanusa.com/downloads/0/minikits/manuals/manual_mk111.pdf

It can be modified to do what you say you want.
Click to expand...

Hmmmm....... in that case, forget the electronics! ;O)
 
"Guv Bob" <guvbob2003@yahooooooooooooooo.com> wrote in message news:lKednb_fcOnJU4bPnZ2dnUVZ_oWdnZ2d@earthlink.com...
"Spehro Pefhany" <speffSNIP@interlogDOTyou.knowwhat> wrote in message news:l20n191irlkc14q13f9on9l0tctgtihjva@4ax.com...
On Sun, 25 Aug 2013 23:29:54 -0700, "Guv Bob"
guvbob2003@yahooooooooooooooo.com> wrote:

"Guv Bob" <guvbob2003@yahooooooooooooooo.com> wrote in message news:1_udnQ7rBpNjRo7PnZ2dnUVZ_sidnZ2d@earthlink.com...
Names can be confusing, so here's what I'm doing....

http://img43.imageshack.us/img43/7434/wvm.gif

When 12VDC is applied to the input, I need a 12VDC output for 5 seconds. Then output will go back off and stay off until the input goes to zero. Then cycle starts again.

Current for both legs is in the 10-50ma range.

A simple on-delay timer would work but I'm having trouble finding one with NC contacts. Tons of stuff $100+, but for this application, it has to be under $20.

==
Thanks for all the tips and good info. I had wanted to put something together from components but my brain is too far behind these days. I'm going to give this a shot and hopefully I'm not picking the wrong one. It's $5 at Frys...

Velleman MK111
http://www.vellemanusa.com/downloads/0/minikits/manuals/manual_mk111.pdf

It can be modified to do what you say you want.
Click to expand...

- Hmmmm....... in that case, forget the electronics! ;O)


http://www.vellemanusa.com/downloads/0/minikits/manuals/manual_mk111.pdf

If I disconnect pin 7, would that make it a one-shot pulse?
 
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