This circuit with zener diodes was found in documentation from the 90s. The zener diodes determine the lighting point of the LEDs. The circuit is for 12 V automotive batteries.
This circuit that emits siren sound can be used in a fire alarm. We found it in an old American...
This circuit generates sinusoidal signals from 15 Hz to 15 kHz. The circuit is from Electronics Now...
In the figure a circuit that is the basic application of NE567 for the detection of a tone applied to...