This circuit generates noise pulses for audio equipment probes. The circuit is from a 90’s 303 Circuits. The operational amplifier is an input FET type.
This simple 4-bit digital-to-analog converter was found in a 1974 publication. The transistors can be the...
The optocoupler in the figure uses common transistors and a phototransistor to drive a sensitive relay...
The component used, which is not common today, is an electronic attenuator. In this application of the...