The voltages in an adjusted range in the trimpots are indicated by 3 LEDs. The LEDs indicate when the voltage is below the range, above the range and in the range.
This circuit was found in a 1968 EEE and can be implemented with any current general-purpose transistor....
Two 3-terminal regulators like the LM317 can be used to "clip" a sinusoidal signal, in order to...
This circuit was found in a Radio Electronics from January 1965. The relay is 9V, but we can...