This filter was found in a Texas Instruments manual based on an operational amplifier 741. Other operational can be used and, with the indicated components, the rejection frequency is 2 kHz.
This instrument, based on a 555, measures frequencies up to 1 kHz, but its scale can be modified by...
This variable timing circuit was found in 1964 General Electric documentation. Circuit uses PUTs...
This circuit, suggested by Sylvania in a 1956 publication, serves as an experimental stage for a...