"John Fields" wrote in message ...
On Tue, 20 Aug 2013 14:12:28 -0700, "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.

---
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?

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 0.47µ
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