This 80's circuit has been winning. It is a 1 000 gain sample and hold circuit and an offset current setting. The configuration can be adapted to operate with modern equivalent components.
This circuit is from a Popular Electronics from the 90s. The integrated circuit admits equivalents...
This very interesting project was obtained in a 1980 publication. It consists of a device that is...
This circuit beeps when the sensor is triggered by the opening of the freezer door or other...