Infra Red Link

A basic Infra Red Link for audio communication for distances upto 3 metres.

IR Link

Ovo je shema jednostavne bez?i?ne komunikacije sa malo komponenata .Diode d1 i d2 su infracrvene le-diode ,a foto transistor je tako?er infracrveni radi ?to manjeg vanjskog utjecaja .Domet ure?aja je oko 3m no on se mo?e promijeniti brojem le-dioda i naponom koji se dovede na diode.Na izlaz se ?ak mogu i direktno spojiti slu?alice.Link mo?e poslu?iti i za prijenos drugih vrsta signala..Na popisu komponenata nema kriti?nih dijelova i izrada sklopa je jako jeftina. Uz malo pa?nje ne moe da ne radi.
P.S Transistors can be replaced with 2N3904 and 2N2222

In his circuit Milan has created a basic Infra Red transmitter and receiver. The transmitter comprises a single
amplifying stage driving two series connected IR LEDS. The input source is connected to J1. Please note that
the device will pass a small DC current through it and also directly bias the transistor. A suitable device is
therefore a high output crystal microphone. These can produce high output voltages up to 1 Volt but this will be
reduced by the transistors low input impedance.

The receiver is three stages, the first stage being a phototransistor. Stages two and three form a high gain
darlington emitter follower, the bias for the whole stage derived through R2 and the phototransistor itself.
C1 and R3 form a filter to reduce interference from flourescent lighting and other hum sources. The output is via
Jack J2. Note also that the output device will pass a small DC current so a medium impedance loudspeaker or
headphones are a good choice here.

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