Description.
This is a very simple cable TV amplifier using two transistors. This amplifier circuit is most suitable for cable TV systems using 75 Ohm coaxial cables and works fine up to 150MHz. Transistor T1 performs the job of amplification. Up to 20dB gain can be expected from the circuit.T2 is wired as an emitter follower to increase current gain.

Circuit diagram.

cable-tv-amplifier

Notes.

  • The circuit can be assembled on a Vero board.
  • Use 12V DC for powering the circuit.
  • Type no of the transistors are not very critical.
  • Any medium power NPN RF transistors can be used in place of T1 and T2.
  • This is just an elementary circuit. Do not compare it with high quality Cable TV amplifiers available in the market.
Author

47 Comments

  1. dhanasekar

    what is equivalent transistor for 2SC4308 and 2SC1324

  2. i need a circuit of
    frequency 47-862MH
    level 45-90dBuV(75ohm)
    band 8MHz
    symbol rate 6.900Maud
    imudence 75ohm

    • pls if you have a soft copy of Semi-conductor Data book, pls send it to me

      am in great need to find alternative component to complete my project.

  3. muthulakshmi

    from above notes I cant understand the operation of this circuit plz explain briefly

  4. The amplifier works, but it runs at about 600MHz transmission. The switching transistor 2SC2570 used. Closed metal box, with a stable 12V power supply. F connector. What could be the problem?

  5. abimbola

    How will i applied it on my cable TV decoder.and will it work if i built this at home

  6. S.Dhamodharan

    Respected Sir,

    I have finished UG-BSc electronics and communication system on Apr 2012. Now I am searching Job about electronics relationship.If any vacancy
    in there.Please kindly inform me.

    Thanking You

    By
    Dhamodharan.S

  7. Since Comcast and Charter are at 1Gigahertz,
    how about a circuit to amplify at that frequency?

  8. maaz ranjha

    hi i am a electricion and try to do the small small projects of domestic level so it is a so better circuit of cable tv circuit.thanks

  9. please send me a Circuit diagram of power saver if you have….thanks

  10. Aye Su Mon

    Hi i m electrical student.I took this circuit for my project.I want to know how to convert this circuit to simplified h-parameter equivalent circuit with complete calculation.And how the resistors are connected?Are they in series or parallel?

  11. Aye Su Mon

    Hi!I am Aye Su Mon.I am an electrical student.Now I have to do Analog Electronic circuit project.May I know how to simply this circuit using calculation?How do the two transistors work and how about the relationship of the resistors?Thank you.

  12. haaaaaaaaa what a wonderful bullshit. 150MHz for cable tv !! what a big funny lol . do u hav any cable amplifier upto 850MHz ….

  13. Can we use it where cable have 200 channels ??

  14. Jitendra

    Can it be used for UHF band(300 MHz and 3 GHz) apart from VL and VHf band? If not, then what changes should be made to do this?

  15. Seetharaman

    Hi VIC it can operate at that frequency also.
    Hi Deepak within INR 100 you can can assemble it.
    Hi Rajesh you can try with RS Components SD road Hyd – 3.
    also Bank street Hyd – 95. 2SC2570 is a very popular UHF transistor.

  16. Does this work on a VHF Radio system. i am going to use it on 157.4250 Mhz as a pre amp to a repeater

  17. What will be the cost for the components.I have really bad cable tv connection.

  18. Where would i found 2sc1324,bfr36,bfw16,2sc1068 or 2sc 2570 in hyd

  19. Seetharaman

    Hi Rajesh 2SC2570 is the most popular Low Noise UHF transistor available in all electronic spare parts shop in India. If you are at Bombay try Visha Electronics or Vega Kits or any shop at Lamington Road.

  20. Where would i found these transisters

    pls tell me the place and shop name

  21. Pingback: aunl » Kablo TV Yükselticisi (Amplifikatör)

  22. sir, I want a FM BOOSTER circuit,with out trimmers because these are very difficult to get from shopes.thankyou.

  23. seetharaman

    Hi Chary try using 2SC2570 for both the transistors. You can find the difference in the noisey channels both in audio and video or atleast in audio (the frying noise with audio will get reduced). Finally you may try a 6 turns close wound air core coil of 6mm dia with 18 SWG super enameled copper wire, between C2, R5 junction and ground.

  24. Sir,
    I cant getting any changes in quality of picture, and I am using Transformer with rectifier and capacitor for providing 12v supply. please solve my problem,
    Thank you

  25. seetharaman

    Hi Dignto no need, the same transformer can be used. the circuit will consume only 16mA. (it is just peanuts for the transformer). So you can comfortably use your tansformer with rectifier smoothing capacitors and regulator.

  26. Oh no! Where will I get so lower Current transformer . I have a 12V and 600mA transformer only . Can I use this transformer in this circuit ?

  27. seetharaman

    hi Muhammad Ibraheem no. this circuit is not suitable.

  28. HI,
    I wanted to ask whelther this circuit would be ideal to amplify wifi signals around 2.4 to 2.5 Ghz.I was working on a project in which i have to spread my wifi signals in 10km radius,i can use this circuit in series to amplify signal many many times,ill use atleast 15 of these circuits in series

  29. How much current do I need for this circuit ?

    Please reply ………..

  30. 12V and What Amp.? Transformer will I use ? Will It work in more than 100 Channels TV Cable ? And Is it For a Single TV ?

    Actually, I have a Television and Computer TV Card in my home . When My dad watch TV, then my TV Card display poor quality Picture . Otherwise it is good . May be it is happennig for less line gain when running two sets (Television+TV Card) .

    If I use this Amplifier for my TV Card then will it solve my problem ?

    -Thanks

  31. seetharaman

    Hi the most popular 2SC2570 UHF low noise transistor used in VCR RF amplifier can be used successfully.

  32. Md. Sumon Biswas

    Zaeem Ahmed,

    Transistor 2SC1324 subtitute BFR 36, BFW 16, 2SC1068

    Thanks

    Sumon