Found in a 1960 General Electric documentation, this crowbar circuit blows the fuse in case of excess current. The circuit is for 12 V sources triggering between 14 and 17 V.
This circuit was found in a 1987 magazine. It measures monitors the heartbeat through a...
This crystal-controlled circuit was obtained from a 1980s documentation. The power supply should be 5...
This circuit is from 1957 Raytheon documentation. The phone must be high impedance with 600 ohms...