This circuit with transistors of the time was found in the November 1972 Radio Electronics magazine. The circuit also generates a sawtooth signal for use on an oscilloscope.
We found this circuit in the Linear Applications Handbook of the National Semiconductor of 1994....
This circuit was obtained from a 90sLinear Technology documentation. It is a current source that...
This is a possible circuit for the receiver of the previous circuit. Other circuits can be found...