This circuit is from a Hands-On Electronics from the 90s. The integrated amplifiers used are well known. The range is a few tens of meters depending on the resistance of the cables.
This circuit was found in a 1969 Mullard documentation. Used transistors can be replaced with...
This is a simulation of a Relaxation Oscillator using a programmable unijunction transistor (PUT). The...
This constant current source is from the LM11's own factory manual used in the application. The circuit is...