This precision speed control was obtained in an Electronic Design from the 90's. The output final stage power transistors must be in accordance with the motor power.
This circuit was taken from the 1960's Mullard Transistor Manual. Information about the coils is...
This bridge circuit is designed for 8-ohm speakers delivering a few watts of power. The circuit is from...
This alarm, from a 1996 magazine, can be fitted with two BC548s in the original configuration...