Found in 90's Electronic Engineering this circuit can be used to measure phase angles between two signals from 0 to 180 degrees. The components used admit modern equivalents.
This circuit can also operate with SW and even VHF signals up to 150 MHz. The circuit can be...
This integrating circuit multiplies the time that can be obtained with a 555 timer. We find it in...
This transmitter for the 7 MHz range, as we can assume by the number of turns of the coil, since the...