Found in Ferranti's 1969 documentation this circuit has a maximum operating frequency of 7.5 MHz. The circuit can be designed with modern transistors.
This circuit appears with variations in other points of this section. This version is from...
This circuit was obtained from a 1970s RCA. The circuit uses LDRs as sensors. The resistors depend on the...
This circuit can be used with common drills connected to the 110 V network. With change of R1 and...