The circuit shown is for testing both signal diodes (low current) and rectifiers (high current). The circuit is from a 2000 Poptronics, and the transformer has a secondary winding of 100 to 300 mA.
This very simple oscillator, with only one transistor, was found in a Japanese magazine in 1967....
This simple bridge circuit can be used for impedance or resistance measurement using a high...
This circuit has the intensity of the signals controlled by the light that falls on the sensor....