This audio configuration of televisions from the 1960s was found in a Mullard transistor reference manual. Transformers are the critical components.
This circuit of a 1991 PE Hobbyst Handbook allows the brightness of the incandescent lamp to be...
This circuit is from the old RCA transistors manual of 1964. The transistor can be the BC558 and...
Originally this circuit is from an English magazine, but I found it in Argentina's Radio Chassis...