Description.
Here is a simple IR headphone circuit that is suitable for listening to TV or radio with out disturbing others. For beginners the IR headset is a better option than FM head sets because they often produce desirable sound quality with out tuning as well as difficult impedance matching that is often done in radio circuits which is difficult for beginners.
Transmitter.Â
The audio signal is coupled to the base of T1 (BC547) by an audio transformer. The T1 pre amplifies the signal. The transistor T2 (BD 140) drives the IR LED’s which transmit the sound as IR beams. The red LED provides fixed bias for theT2Â as well as a power on indication. The transmitter has a 5m range under normal conditions. A 9V battery can be used to power the transmitter.
Receiver.Â
The photo transistor T3 receives the IR signals. The collector of IR is connected to base of T4(BC548) which amplifies the signal together with T5 (BC549)to regain the audio signal transmitted. The transistor T6 drives the headphone to reproduce the sound. The receiver can be powered by using a 9V battery.
Circuit diagram with Parts list.Â
- Infrared (IR) Headphone Circuit
Notes.Â
- The audio transformer can be easily obtained from a old transistor radio. It should be connected with the low impedance winding (thicker) to the audio input (TV or radio) side.
- The presets VR1 & VR2 can be adjusted for improving clarity.
Does hs0038 phototransitor work with this set up
Can u tell me which one of t3 or photo transistor is used in this
i want to know the type of 10k&100k resistors used in the circuit. & working of the circuit.
please show me the video of this
i want the value of transformer and and any online(india) stores for these components?
how can I increase its range upto 50 or 100 meters???
Sir the circuit is just awsome but can we use BC558 instead of BEL 187 because it is not available.
You can try S8050, BD135, 2N1711 etc NPN medium power transistors. BC548 may not be in a position to handle. BC558 is a PNP transistor of low power, hence cannot be used.
I have tried the receiver circuit sir. But it is dostorted… the schematic shows that it used just bc 549 and bd139 but on the detailed it has bc548? Can u clarify it to me
Since it uses only 9 volt BC149C is most suited but BC148B also can be used. To reduce distortion in the transmitter there is no bias for T1 only with signal it has to conduct means class C operation. Please use a 270K 1/4 resistance between 9volt +ve supply to VR1 & R1 junction (it can be any value between 100k TO 330k till distortion becomes very minimal.)
How can I study electronic circuits online?
Does direct sunlight affect this transmitted IRrays??
if yes then how to reduce that effect??
What is the specification of the transformer that you use after the audio signal input?
regards.
What the approximate range between the receiver and transmitter?
Can you give me more details about the type of photo-transistor and the detailed description for this circuit.
Thanks
can anyone give me the working of the circuit ,which transformmer is used and some theory n application of this project
The transformer used here is a small audio frequency transformer (type no LT700). Such transformers can be easily found on the output stages of old transistor radios).
I think the description i gave is quite enough.
I you need a very detailed description, then comment here. I will add it here.
Hi could you please make the pictures clearer thanks mike
Hi could you make the pictures a little clearer as i cannot see what some of the parts are
thanks