This old fashioned transistor amplifier was found in a publication of the year 1958. Transformer are the critical components in the circuit and power comes from 6 D cells.
Found in documentation from the 90's, this circuit has a narrow pass band around 1 kHz. The...
This circuit was found in a Radio Electronics magazine from November 1991. The circuit operates at 2.2...
Found in old documentation, this circuit has only the most difficult component to obtain the PUT....