Found in a Popular Electronics from the 90s, this circuit uses common components with several operational options, including the use of an optocoupler that allows its application in a shield.
This circuit multiplies the input resistance of an operational amplifier. As the indicated...
This conventional flip-flop configuration with two transistors was found in documentation from the...
The input impedance of this amplifier is of the order of 1014 being the same indicated for pH...