Two Tone Alarm with IC LM3900



Circuit Two Tone Alarm with IC LM3900

This be Two tone alarm use op-amp IC number LM3900 (Quad Amplifiers) perform produce the frequency square wave 2 level , be high frequency and low then mix the sound in the end danger beep that is appropriate it has can to link up a loudspeaker with ,using power mosfet then have better use transistor which complicated and not durable. This circuit convenients for power supply 9V to 12V sizes and 8 ohm 20watt size loudspeakers will by large-sized have a voice loud small-sized better.


This entry was posted on Thursday, May 17th, 2007 at 11:46 pm and is filed under alarm systems, Audio - Alarm, basic electronics. Both comments and pings are currently closed.