This interesting circuit for the RDA8851 allows you to obtain two volumes with a simple touch. The circuit is from an Electronics Now from December 1988. Note the amplifier voltages.
Found in documentation from the 1970s, this circuit uses an oscillator and a display to warn of...
This circuit simulates a low-level siren and can be supplied with voltages from 5 to 15 V....
The filter shown in the figure, using only an operational amplifier, is characterized by allowing 1...