This circuit lets through the 300 Hz to 3kHz range that corresponds to the human voice. We found it in the Radio Electronics magazine of February 1990. The circuit uses both parts of the LM381.
The selected circuit was obtained in a Texas Instruments opto-electronics manual. The transistors can be...
This circuit is suggested by Texas Instruments' Linear Circuits Applications. It consists of an...
This is a typical quartz crystal oscillator for the 3.5 MHz frequency (80-meter range) used in...