This amplifier stage was equipped with a Motorola radio from the 70s. The transistors were from that time and the single transistor output used an autotransformer.
This Nixie pipe circuit was found in 1965 documentation. Note the high supply voltage. Appropriate...
This circuit is from a 1976 publication, but it can be assembled with modern components. For the...
Found in Popular Electronics from the 90's, this circuit consists of an audio oscillator for Morse...