Found in Unitrode documentation from the 1980s, this circuit makes use of PUTs, currently common components. The circuit must be powered with voltages around 15 V.
This well-known configuration was found in a 1982 publication. Other operational amplifiers can be...
Suggested by General Electric in 1965 documentation this circuit is intended for the 120 Vac...
Combined with the two previous circuits, we can create a simple multimeter with this circuit. The...