I recently constructed the second 741 Op Amp Thermal Cooling Fan Controller for the power supply of the 145.550 Mhz RF Link Motorola Radio. This one has an adjustable pot to control the thermistor's reaction time . Previous posts on this Blog describe how this circuit function and operate.
Once again a money saving hint due to the unavailability of rubber grommets.
I purchased 4 round insert plugs (16mm x 4) for R8.23. Grommets are far more expensive while the courier costs are more than the components. All I did was drilling a hole in the center of the plug, the size that just allow the wires through. Simple and cheap and works like a charm.
Here is a few photos of the completed project.
