This circuit uses a common multimeter on the voltage scale. The calibration of the scale should be done based on transistors with known gains.
This proximity (capacitive) alarm triggers a relay that, in turn, triggers an audible warning...
This sensitive circuit was found in old documentation. The SCR can be any of the 106 series and...
This traditional multivibrator configuration uses an LDR as a sensor. The circuit emits sound when...