intercom circuit diagram for room
intercom circuit diagram
intercom circuit diagrams
P1____ 22K Log. Potentiometer R1___ 22K 1/4W Resistor R2,R3____ 100K 1/4W Resistors R4___ 47K 1/4W Resistor R5_____ 2K2 1/4W Resistor (See Notes) R6_____ 6K8 1/4W Resistor R7________22K 1/2W Carbon or Cermet Trimmer R8_______ 2K7 1/4W Resistor
C1,C6_____100nF 63V Polyester or Ceramic Capacitors C2,C3___ _10µF 63V Electrolytic Capacitors C4________22µF 25V Electrolytic Capacitor C5________22nF 63V Polyester or Ceramic Capacitor C7________470µF 25V Electrolytic Capacitor
Q1_________BC547 45V 100mA NPN Transistor
IC1________TDA7052 Audio power amplifier IC
SW1_______ SPST miniature Switch
MIC________Miniature electret microphone
SPKR_______8 Ohm Loudspeaker
Full-duplex Intercom PCB for your office and house
As both microphones and loudspeakers are always in operation, a special circuit is used to avoid that the loudspeaker output can be picked-up by the microphone enclosed in the same box, causing a very undesirable and loud “howl”, i.e. the well known “Larsen effect”.
A “Private” switch allows microphone muting, if required.
Full-duplex Intercom PCB for your office and house
The circuit uses the TDA7052 audio power amplifier IC, capable of delivering about 1 Watt of output power at a supply voltage comprised in the 6 – 12V range
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thanks!
April 7, 2010 @ 20:39