Found in Motorola's 1967 documentation this circuit can use any general-purpose transistor. The signal should be applied to a good amplifier. The noise diode can be replaced with a common one.
April 2017 - The new Maxim Integrated MAX20733 and 20745 switched regulators are available from...
The indicator for this circuit is a mini buzzer with a 1.5 V oscillator. The circuit can also be...
This 80's documentation circuit includes an amplifier of the era. Used integrated circuits are...