This circuit for light modulated in frequency (FM) operating at 50 kHz was found in a 90’s Electronics Now. The circuit has an active filter. Modern equivalent transistors can be used.
Found in Motorola's 1965 manual, this full-wave dimmer controls a load that depends on the used...
The two adding and differentiating circuits with operational amplifiers given below were obtained from...
This sophisticated circuit was found in the November 1978 issue of Radio Electronics magazine. Based on...