Intercom

Posts Tagged ‘Intercom’

LM390 MiNi Intercom

Here is Intercom circuit,It Very easy Circuit. Use IC LM390 for Amplifier Sound Form Speaker or Mic.
Control S1a change Talk and Listen.
See to Detail in Circuit.

Be the first to comment - What do you think? Posted by admin - September 6, 2007 at 12:58 am

Categories: Audio diagram, Basic electronics Tags: headphones, Intercom, lm390

Doorphone Intercom by IC LM386

For the first time, this circuit was designed by two authors, Mr Laurier Gendron of Burnaby in British Columbia, Canada, and myself. Please make sure you visit Laurier’s web site, Handy Dandy Little Circuits. This page is also available in French by clicking on the flag.
In this doorphone circuit,an 8 ohm speaker is used both as a microphone and also an output device. The BC109C stage amplifies in common base mode, giving good voltage gain , whilst providing a low impedance input to match the speaker. Self DC bias is used allowing for variations in transistor current gain. An LM386 is used in non-inverting mode as a power amplifier to boost voltage gain and drive the 8 ohm speaker. The 10k potentiometer acts as the volume control, and overall gain may be adjusted using the 5k preset. The double pole double throw switch, reverses the loudspeaker positions, so that one is used to talk and the other to listen. Manually operating the switch (from inside the house) allows two way communication.

Source : http://www.zen22142.zen.co.uk/Circuits/Audio/doorint.htm

Be the first to comment - What do you think? Posted by admin - June 26, 2007 at 3:34 pm

Categories: Audio diagram, Circuit diagram Tags: Circuit diagram, Communicator, Intercom, LM386

This circuit was requested by an school teacher. It is a simple intercom that anyone can put together and get to work. It is based on the LM380 IC chip. This chip is able to put out 2 watts of power if it is heat sink properly. The following pins should be grounded and attached to a foil to dissipate the heat. Pins 3,4,5,10,11,12 should all be grounded. The circuit works as follows. Switch 1 is a double pole double throw switch. In one position is the talk position and in the other is the listen position. In the diagram shown the switch is in the talk position for the speaker on the left. Talking into the speaker inputs a signal to the IC chip through the matching transformer T1. The output from the IC chip goes to the speaker on the right. If you put the switch in the other position the speaker on the right is the talking unit and the speaker on the left listens. Volume is controlled by the 1meg ohm pot R1. This circuit is very basic but is a good start for a child or anyone starting new in electronics.
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Source: :: http://home.maine.rr.com/randylinscott/apr98.htm