555 Spike protection
Posted: Sat Dec 03, 2005 1:32 am
Hi,
Ive been building a circuit to replace the Fuel pump relay control output from my FI ECU. I've been having problems with the 555 ic either emitting a puff of smoke and dying or melting Since it happens after repeated cranking and starting, i'm thinking its a voltage spike thats killing the 555. I can run the circuit all day once the car is started and not have any issues.
Would a 15V 5W zener across the power input provide enough protection againts spikes present during cranking/starting in a car?
<img src="http://members.optusnet.com.au/kang5/Saab/untitled.JPG" alt=" - " />
Thanks,
Ben
<small>[ December 03, 2005, 01:32 AM: Message edited by: ejukated ]</small>
Ive been building a circuit to replace the Fuel pump relay control output from my FI ECU. I've been having problems with the 555 ic either emitting a puff of smoke and dying or melting Since it happens after repeated cranking and starting, i'm thinking its a voltage spike thats killing the 555. I can run the circuit all day once the car is started and not have any issues.
Would a 15V 5W zener across the power input provide enough protection againts spikes present during cranking/starting in a car?
<img src="http://members.optusnet.com.au/kang5/Saab/untitled.JPG" alt=" - " />
Thanks,
Ben
<small>[ December 03, 2005, 01:32 AM: Message edited by: ejukated ]</small>