Found in a 1947 publication, this 7-tube amplifier uses four tubes in the output stage. The circuit uses a power source with 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...