Re: Fan speed control by OP of amp.
Back in 1983, in my first job, I designed a video processor. This was to be mounted in a helicopter, with rather a large temperature range. So I used a thermistor, an op-amp controller and a power stage to run the fan.
It did not operate until a preset temperature, then after a kick in transient to get it going the fan ran linearly with temperature until it reached it maximum operating voltage.
All back in the days of the lm741 and similar stuff.
Craig
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