Found in an Electronic Design and 1970s, this circuit uses transistors of the time. The transistors can be replaced with equivalents and the relay is 12 V depending on the power supply.
This circuit measures alternating voltages on 5 scales and its accuracy depends on the tolerance of the...
This circuit was obtained in an American documentation translated in the 80's. The circuit can be...
Figure bellow shows another configuratíon for a Iow-frequency sine wave oscillator using CMOS...