This 4-tube counter was found in Radio Electronics magazine from December 1959. The circuit uses a coil as a sensor to detect the passage of metallic parts or magnets.
This circuit consists of an amplifying probe for oscilloscopes and other instruments that can...
This circuit is suggested by National Semiconductor in its Linear Applications Handbook. It makes...
This circuito from the 1977 GE Semiconductor Manual circuit provides timings from 0 to 90 seconds...