Suggested by Maxim in documentation from the 90s, this circuit has its response curve given next to the diagram as well as the formulas for the component calculations.
This circuit was found in Electronics Handbook, Vol XIII 1993 and consists of a simple direction...
This circuit works only with carbon microphones, due its low impedance. The speaker should be good or...
This is the normal circuit of a relaxation oscillator using an unijunction transistor such as the...