In the figure we have a simple thermometer with NTC, using an analog current indicator. The adjustment is made in the trimpot and the power is done by batteries.
This circuit is from an American publication in 1998. The integrated circuit used is not very easy...
This stepper motor control was originally designed to use a PC's parallel port and is quite simple...
The crystal in this circuit can have frequencies from 100kHz to 8MHz. Capacitor C2 adjusts the...