The sensor is S1 in this alarm that we found in a Radio Electronics magazine from May 1971. Several sensors can be used in series. The SCR supports equivalents from the 106 series.
Found in a Raytheon circuit manual from the 1960s, this circuit uses the CK722 and a...
With this circuit it is possible to measure RF signals with a common multimeter. Signals up to 200...
This circuit was found in a 1967 US publication. In it we have the implementation of a ring...