room noise detector circuit schematic


Posted on Feb 5, 2014

This circuit is intended to signal, through a flashing LED, the exceeding of a fixed threshold in room noise, chosen from three fixed levels, namely 50, 70 & 85 dB. Two Op-amps provide the necessary circuit gain for sounds picked-up by a miniature electret microphone to drive a LED. With SW1 in the first position the circuit is off. Second, third and fourth positions power the circuit and set the input sensitivity threshold to 85, 70 & 50 dB respectively. Current drawing is 1mA with LED off and 12-15mA when the LED is steady on..


room noise detector circuit schematic
Click here to download the full size of the above Circuit.




Leave Comment

characters left:

New Circuits

.

 


Popular Circuits

Stepper Motor Driver Circuit
555 LED flasher II
Low-Frequency Prescaler
Oscillator Core Examples
radio controlled electronic flash
Power Supply Circuit
headphone jacks
Clap Switch circuit diagram
Cat Repeller CircuitRepellentCircuit555 Ultrasonic Circuit
LMD18400 for four-phase stepper motor drive



Top