Suggested by a 90s EDN, this circuit supports almost any LED as a source and a phototransistor as a detector. The circuit operates with a PLL 567 at a frequency of around 40 kHz.
This circuit allows the measurement of very weak currents indicated on an analog instrument or...
Found in National Semionductor documentation this circuit combines a tone control with an...
Found in a 73 magazine from the 1980s, this circuit generates signals from 3.2 to 22 MHz. FETs can be...