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.
This circuit generates pulses whose duration determines the position of a remote-control servo. The...
This circuit uses a piezoelectric tweeter to emit a powerful continuous sound above the audible...
This circuit generates sinusoidal signals that depend on the input oscillator. The circuit is from...