We found this good amplifier in a Japanese publication of 1966. Transformers are uncommon nowadays and the power supply is included. Power is a few watts.
This circuit activates a relay when the conducting bars (probes) are held by a person. The circuit is...
This circuit has been found in operational documentation of the 1970s. The circuit has a fail-safe...
This conventional Hartley oscillator circuit with an audio output transformer was found in a...