12v 555 timer circuit 1-5 minutes with motor

Thread Starter

HarrisonRedwood

Joined Feb 9, 2016
16
I need to make a variable timer circuit using a 555 timer that I can control to be on for 1-5 minutes. I have posted a picture of where I am so far but the problem is that the 12v motor stays on until the power is stopped. The potentiometer doesn't seem to do much. I'm not sure what the problem is?

Also is it OK to run the motor and circuit from the same power supply or should I use a relay between them?

Help is much appreciated, cheers.555.jpg
 

GopherT

Joined Nov 23, 2012
8,012
I need to make a variable timer circuit using a 555 timer that I can control to be on for 1-5 minutes. I have posted a picture of where I am so far but the problem is that the 12v motor stays on until the power is stopped. The potentiometer doesn't seem to do much. I'm not sure what the problem is?

Also is it OK to run the motor and circuit from the same power supply or should I use a relay between them?

Help is much appreciated, cheers.View attachment 103833

You are changing series resistance from 1,000,000M to 1,010,000M. That is hardly any change.
 

#12

Joined Nov 30, 2010
18,167
You could run into leakage problems with the capacitor. Electrolytic caps that large are not guaranteed to leak less than 8 microamps.
If the capacitor never charges up enough to flop the output, you know where to look.;)

Reality intrudes.:(
 

Thread Starter

HarrisonRedwood

Joined Feb 9, 2016
16
I have tried making all of the changes said above, however the same problem still remains. The motor stays on forever and doesn't stop, I can't seem to find any solution to it or any similar circuit that does the job.
 
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