Smoke-detector


Posted on Jan 22, 2013

This circuit comes from U.S. Patent 3, 778,800, granted to BRK Electronics in Aurora, IL. The circuit provides a smoke detector with an alarm for both smoke and low batteries. The R6/R7 voltage divider monitors the battery and will turn Q2 and Ql off when the battery voltage falls too low. The smoke-detector chamber will also cut Ql off when it senses smoke.


Smoke-detector
Click here to download the full size of the above Circuit.

Ql via Q3, triggers SCR Dl and sounds the alarm. Capacitor Cl provides feedback that causes the alarm to sound intermittently. The smoke detector and low-battery circuits sound the alarm at two different rates.




Leave Comment

characters left:

New Circuits

.

 


Popular Circuits

10 LEDS Audio level vumeter
FUNCTION GENERATOR
4 MHz Modulated Oscillator (2N4401)
Paper-sheet-discriminator
Automatic blind hooked up to existing projector screen using Arduino
STA550 - 2 x 70W Audio Amplifier Circuit
PreamplifierCircuit DCF77
16 G— 2 LCD Volt Meter & Ampere Meter With PIC Schematic Diagram
DQPSK Pi4DemodSync
Multiple channel SR-Buck converter of the trimmer module VRM of voltage
circuit schematic symbol for buffer with control input
How to test a triac
Boost Switching Converter Design Equations
Micropower type 1 SE
FM receivers with PLL
TC35I use wireless data transmission and GSM communication module circuit design schematics



Top