Suggested by Mullard in an old documentation, this circuit is based on a common phototransistor and on transistors that may be the modern BC548.
This experimental circuit is from a 1975s publication. The coil consists of 80 turns of wire AWG...
We found this circuit in a 1964 Electronic Design. It divides the frequency of a 20 MHz signal by...
Found in a 2005 Linear Technology application manual, this circuit provides outputs from a current...