This telegraph monitor was found in an American documentation for radio amateurs from the 1970s. The indicator is a common 1 mA full-scale milliammeter.
This useful circuit is used to test the insulation of cables, appliances, leaks in high voltage...
This circuit was found in a Texas Instruments linear application manual from the 1990s. The...
With this circuit it is possible to select the upper or lower side band on an SSB transmission by...