This control for 12 V drills was found in a 90s Elektor. The components are current, and Q1 can be replaced by a TIP42 mounted on a heat radiator.
The National Semiconductor LM675 operational amplifier can provide up to 3 A of output current. In the...
We found this circuit in a 1969 Mullard documentation. The same configuration appears elsewhere in...
Found in a PE Hobbyst Handbook of 1991, this circuit was originally proposed to time photographic...