This circuit for a digital module was found in the September 1989 Radio Electronics magazine. The source must be symmetrical to the operational amplifier.
This circuit was found in 80's Popular Electronics. The circuit uses an infrared-sensitive phototransistor...
This circuit, which in our times would be called a shield, can also be used with other loads. The...
Found in Philips documentation from 1968 this circuit operates at frequencies up to 10 MHz with 76...