This PNP transistor power stage was found in the May 1969 issue of Radio Electronics magazine. The circuit uses a transformer for excitation and requires 10W input for full output power.
This common configuration source with diode bridge and single winding transformer was found in a...
This 2009 circuit is a bilateral call warning. Easy to build, using light communication between two...
This circuit was found in a 90s Popular Electronics. The integrated circuit used is similar to the 741....