This circuit uses an optical coupler to indicate a phone call through a lamp. The circuit is from a Hands-On Electronics from the 90s. The lamp must be incandescent.
This circuit was found in old documentation, but the setting applies to any operational. Resistors...
The 4047 is a monostable/astable CMOS multivibrator. The basic con- figuration is triggered by the...
Found in older Signetics documentation, this circuit generates signals from 30 Hz to 25 kHz....