This is an amplifier circuit intended for modulating transmitters. The 5-tube circuit is from an American manual from 1947. The power supply uses a transformer.
This circuit was found in an American magazine in 1978. It activates a relay when the speed of a...
This second-order low-pass Salen-Key filter was obtained from an American 1980s documentation. Formulas...
The circuit shown in figure 1 generates an intermittent tone in a piezoelectric transducer when...