This circuit was obtained in a French documentation from 1981 and can be easily assembled. The analog instrument itself can be replaced by the current scale of an ordinary multimeter.
Using a CA3130, we found this circuit in an English publication from 1977. The circuit must use a...
We found this circuit in an American documentation from the 90s. The consumption is only 1 uA in...
This 1967 Electronics World circuit is suitable for frequencies up to 1 MHz. The setting applies...