This circuit uses a quadruple operational amplifier of the time. The circuit is from the 70s but can be implemented with modern operators that require the use of a symmetrical source.
Found in an Electronics Now from the 90s, this circuit appears elsewhere in this section and...
This TTL circuit was found in the February 1973 issue of Radio Electronics magazine. The power...
This circuit was found in an old publication about transistor. The original trasistors are...