This circuit was found in a Popular Electronics from the 90s. The counter circuit is not common today. The circuit can be programmed for hourly intervals, according to the values of R4 and C2.
This traditional high sensitivity voltmeter circuit using a FET can employ the MPF102 or BF245 in its...
This noise limiter for low intensity signals was found in a 73 magazine for radio amateurs from the...
This circuit is from a 1976 documentation. It provides a pulsating DC voltage that can be varied...