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  1. audioguru2

    Guitar Aplifier

    A transistor performs like an oscillator if its pins are connected backwards and there is a capacitor on it. Check the datasheet for the photo of the pins on every transistor in your circuit.
  2. audioguru2

    Guitar Aplifier

    The rheostat trimpot in the project is drawn a little different than Fikic draws it but it is exactly the same. It is a variable resistance.
  3. audioguru2

    Guitar Aplifier

    You connected your trimpot as a rheostat (variable resistor). The trimpot in the circuit's schematic is shown differently as a rheostat.
  4. audioguru2

    Home Page

    I use English on all the forums I chat on including this one. I have never installed a "language pack". This site is a Greek one so maybe you need the language pack to see all the Greek things here. I have never looked at the Greek things but I notice that some symbols on projects look odd. Many...
  5. audioguru2

    0-30V Stabilized Power Supply

    The max allowed supply for the TL081 is only 36V but in your circuit U2 and U3 will have 39.4V when the circuit has no load. The resistor (R10) for the input offset voltage adjustment pot (RV1) is the wrong value and connects to the wrong voltage. If your transistors have a high gain then you...
  6. audioguru2

    0-30V Stabilized Power Supply

    We modified the circuit so that MC34071 or TLE2141 opamps can be used with a 28VAC or 30VAC transformer. If you use them in the original circuit then they will have a total supply voltage of 39.6V and will be fine since their max allowed supply is 44V. But there are many other things wrong with...
  7. audioguru2

    0-30V Stabilized Power Supply

    The original circuit uses opamps that have a max allowed supply voltage of only 36V and two of them also use the -5.6V negative supply. The 30VAC transformer will be 31VAC without a load and will produce an unregulated +42.4V supply. Therefore two opamps will have a total of 48V as their supply...
  8. audioguru2

    0-30V Stabilized Power Supply

    The 0.47 ohm current-sensing resistor has a voltage drop of 1.41V at 3A. The transistors and U2 opamp have a range of voltage drop at 3A. Also, the value of the main filter capacitor has a wide range.
  9. audioguru2

    0-30V Stabilized Power Supply

    Many of the parts in the original project are too small so they over-heat, especially the tiny 2N2219 transistor that is used for Q2. Even the transformer is too small so it also over-heats. The transformer voltage is too low so the project will never produce 30V at 3A. The opamps have a max...
  10. audioguru2

    Mimimize power consumption of circuit

    A 9V battery has tiny little low capacity AAAA cells inside. Use three or four AA or AAA cells for much longer battery life.
  11. audioguru2

    Power Supply 0-30V

    Good. Zener diode D8 is a better voltage reference if you change R4 to 1k ohms. Your U2 is overheating because Q1 is turning on and is shorting the output of U2. The negative supply is supposed to be -5.6V which will turn off Q1 if your transformer is only 24VAC. Maybe you have zener diode D7...
  12. audioguru2

    0-30V Stabilized Power Supply

    The original project used many parts that are too small so they got too hot.
  13. audioguru2

    How i can connect this motion detector circuit to this emergency lamp

    The same as I told you on another website and somebody else told you on yet another website: Use the relay that is on the original Ultrasonic Radar project. The relay is driven by TR2. One set of relay contacts can turn on the siren and another set of relay contacts can apply power to the stobe...
  14. audioguru2

    Guitar Aplifier

    The project uses a 48V center-tapped transformer. Since you used a transformer without a center-tap then your transformer should be 24V, not 48V.
  15. audioguru2

    Guitar Aplifier

    The capacitor part numbers on this site are strange. Go to RED Circuits to see the correct parts list for the project.
  16. audioguru2

    can anyone help me connect this circuit

    The original Ulrasonic Radar project drives a relay. Use the relay contacts to turn on the flashing strobe light and to turn on the siren circuit in your other posts.
  17. audioguru2

    Power Supply 0-30V

    The output voltage from U1 has nothing to do with the heat from U2. The output voltage from U1 should be 11.2V which is the 5.6V reference from zener diode D8 multiplied by two by U1 since R5 and R6 make U1 have a gain of 2. U2 heats too much when its output current is too high due to a wiring...
  18. audioguru2

    Power Supply 0-30V

    The original project is a mess of errors. We fixed it but the thread is gone. The fixed version uses a real BD139 power transistor to replace the tiny 2N2219 that was used as Q2 and a 28VAC or 30VAC transformer at 120VA to 129VA is used. The main filter capacitor has a value that is much higher...
  19. audioguru2

    0-30V Stabilized Power Supply

    I have posted the latest schematic and parts list many times. There is a thread about it but I am busy now and will find it later today.
  20. audioguru2

    0-30V Stabilized Power Supply

    You have the schematic for one version (but not the latest) and the parts list for a much older version.
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