I would like to build a little circuit using a LM5555 timer that when 12 volt is applied to the input, it will activate the output and hold it for 45-60 seconds after the input goes away or 0 volt.
What I want to do is add a small cooling fan on the heatsink fo my 60 watt mobile ham radio to help keep it cool when I am talking on it. With just the heatsink after a long trannsmit time ( two minuites) it gets so hot you can not put your hand on it. And I do not want a fan to run all of the time also. I have a nice little 40x10mm fan that only draws .06 ma.
Thanks for your help.
What I want to do is add a small cooling fan on the heatsink fo my 60 watt mobile ham radio to help keep it cool when I am talking on it. With just the heatsink after a long trannsmit time ( two minuites) it gets so hot you can not put your hand on it. And I do not want a fan to run all of the time also. I have a nice little 40x10mm fan that only draws .06 ma.
Thanks for your help.