TV sound infrared repeater circuit

Published:2012/8/21 2:05:00 Author:Ecco | Keyword: TV sound , infrared repeater | From:SeekIC

The repeater consists of two parts of the transmitting and receiving. Figure 1 (a) shows the emitting schematic. The frequency discriminator sound ( audio ) signal is amplified by the transistor VT to promote infrared emission tube. Since the emission intensity of the emission tube is proportional to the current, the infrared light emitted by VD1, VD2 is modulated by the audio signal. In order to prevent distortion, VD1, VD2 must set a certain bias. Figure 1 (b) shows the receiving schematic diagram. The circuit uses an audio amplifier IC LM386. VD is the infrared receiver. When the audio signal is irradiated onto VD by modulated infrared light, it will produce the electrical signal which is the same with audio signal on two ends, then it is coupled to IC for amplification by C1.



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