Found in an Analog Devices documentation from the 90s, this circuit uses operational amplifiers from the time. The power supply must be symmetrical.
This circuit was obtained in a Motorola manual, but it applies to almost any operational...
Found in a 1970 EEE this circuit emulates a zener diode whose voltage can be set to R2. Power...
This circuit different from the timer was found in an English publication from 1978. The circuit uses...