The circuit shown is from Texas Instruments optoelectronics documentation. The input signal is audio and equivalent LEDs can be used. Other operational amplifiers can also be used.
The configuration shown in the figure uses two NPN transistors activating the load when the input...
This circuit was found in American documentation from the 1980s. Its purpose is to use a 170 MHz...
This circuit protects galvanometers that are excited by low impedance amplifiers. The circuit is...