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 circuit is for collectors. It is the circuit of one of the most popular transistor radios of the...
This circuit was found in the December 1991 issue of Radio Electronics magazine. The circuit is...
Found in a QST magazine from the 90s, this circuit broadcasts on different amateur radio bands...