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Need simple delay circuit

P

phila

Jan 1, 1970
0
Could some of you give me some input.
This is a project on my boat.I have a momentary micro switch on my
shifter linkgage that when triped it grounds the neg. side of the
ignition coil which stumbles the engine long enough to shift out of
gear. The switch when tripped goes to ground.I need to build a simple
circuit to hold the coil to ground for 1 to 2 secs to give it more time
to shift.
I was thinking of using a 12 volt relay with the switch wired to to the
ground of the relay and a cap on the positive side of the relay to
delay the relay.
Thinks for any ideas.
 
A

almo

Jan 1, 1970
0
Piece-o-cake, man. 555 Timer, 2n2222 transistor, 12v relay, and 1
diode across the relay.

If nobody else does it, I'll give you a schematic (if I get time.)

Alan
~~~~~~~~~~~~~~~
 
F

Franc Zabkar

Jan 1, 1970
0
Could some of you give me some input.
This is a project on my boat.I have a momentary micro switch on my
shifter linkgage that when triped it grounds the neg. side of the
ignition coil which stumbles the engine long enough to shift out of
gear. The switch when tripped goes to ground.I need to build a simple
circuit to hold the coil to ground for 1 to 2 secs to give it more time
to shift.
I was thinking of using a 12 volt relay with the switch wired to to the
ground of the relay and a cap on the positive side of the relay to
delay the relay.
Thinks for any ideas.

http://ourworld.compuserve.com/homepages/Bill_Bowden/page9.htm#555mono.gif

- Franc Zabkar
 
P

phila

Jan 1, 1970
0
Looks like the simplest one for me would be,555 timer Mono stable (one
shot) circuit,on the link provided,2nd one. I asume I can change the
timing by changing the value of the elect.cap.
 
E

ehsjr

Jan 1, 1970
0
phila said:
Could some of you give me some input.
This is a project on my boat.I have a momentary micro switch on my
shifter linkgage that when triped it grounds the neg. side of the
ignition coil which stumbles the engine long enough to shift out of
gear. The switch when tripped goes to ground.I need to build a simple
circuit to hold the coil to ground for 1 to 2 secs to give it more time
to shift.
I was thinking of using a 12 volt relay with the switch wired to to the
ground of the relay and a cap on the positive side of the relay to
delay the relay.
Thinks for any ideas.

For a brief ~1 second delay, this is simplest:
(View in fixed font)

+12 ---------------+----+----+
| | |+
[D] [Rly] [C]
a| | |
Gnd ---+ +--------+----+----+
| | |
| < | <------ to coil

Micro Relay
Switch Contact

C = 470 uf 25V Cat# 470/25VA
D = 1N4002 Cat# 1N4002
Rly = Omron G6R-1-DC12V Cat# RLY-428

Catalog numbers are from Allelectronics
http://www.allelectronics.com/
The relay specified has contacts rated at 8 amps -
you will need to verify that that is sufficient.

For longer delay, increase the value of C. For shorter
delay, put one or more 680 ohm 1/4 watt resistors in
parallel with C.

Ed
 
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