This circuit was found in the magazine of radio amateurs 73 in a 90's edition. The components are current and the transistor is of general use.
This timer was found in the Texas Instruments 1996 linear applications manual. The relay must be...
This circuit compares two light intensities, providing the indication on an analog instrument. The...
This circuit was obtained in a 1983 publication. It is a 1-transistor voltmeter, capable of...