intercom circuit using fader


Posted on Feb 6, 2014

This is a complete circuit that is shown in the diagram below and is formed by a microphone amplifier built around IC1A, is a design for intercom circuit. In this circuit, there are 2 IC, LM358 that is used to low power dual op amp and 4016 or 4066 Quad bilateral for switch IC. This IC that is used to control the circuit. This is the figure of the


intercom circuit using fader
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circuit. The two microphones (small electret types) are connected to J1 and J2 and the two headphone sets (usually 32 Ohms impedance) to J4 and J5. The iPod headphone output is connected to J3 by means of suitable stereo cable and 3mm jack plugs. R4 acts as a volume control for the microphones and also sets the threshold at which the music will be muted: it should be set once for all and then left alone. When speaking is stopped, the music will revert to full volume after some time-delay, set by R12 and C6. The value of these components can be varied to suit one`s own needs. The headphone amplifiers, despite the high number of transistors used, are simple enough, efficient and, above all, setup-free. They are able to deliver a full 5V peak-to-peak sinewave into 16 Ohm (i. e. about 200mW into two 32 Ohm headphones wired in parallel) with less than 1% distortion @ 1KHz and 0. 7% @ 10KHz. At the standard 40mW headphone power output capability, distortion figures are 0. 6% @ 1KHz and 0. 3% @ 10KHz. R1, R2_22K 1/4W Resistor R3, R20_1K 1/4W Resistors R4_50K 1/2W Trimmer Cermet or Carbon R5_47K 1/4W Resistor R6, R7, R8_100K 1/4W Resistors R9, R10_68K 1/4W Resistors (See Comments) R11, R15, R16_1M 1/4W Resistors R12_470K 1/4W Resistor (See Comments) R13, R14_220K 1/4W Resistors R17, R18_100K 1/4W Resistors R19_470R 1/4W Resistor C1, C2, C5, C7, C8_100nF 63V Polyester or Ceramic Capacitors C3_100nF 63V Polyester or Ceramic...




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