This small tube amplifier appeared in Radio Electronics magazine in February 1958. The circuit is powered by the mains with a power transformer and output with different impedances.
This circuit was found in American documentation from the 90s. The coupler is the type that uses a...
This circuit with a MOSFET is from an old American documentation. The capacitor should be leak...
This circuit activates a relay with a frequency signal determined by the adjustment components. The...