We found this circuit in a Radio Electronics issue from July 1969. The lamp remains on until C1 opens. The time is given by capacitor C1.
This nonlinear gain circuit was found in a 1965 Electronic Design. The configuration can be used...
This circuit uses an operational amplifier that is still common today. The indication is made by...
The circuit shown is from the National Semiconductor's Linear Applications Handbook. The CI is not...