This unusual circuit from a Popular Electronics of the 90s uses LED indicators, operating as a bridge. The components used are common. It is based on the tuning of the signal by a PLL.
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...