Search results

  1. audioguru2

    Newb Question: 12v-80ma transistor switch

    Then it is able to drive the NPN transistor circuit that uses a 2N4401 transistor and a 2.7k series base resistor. Then the relay will activate. When the input voltage drops to about 0.7V or less then the relay will turn off.
  2. audioguru2

    L298n IC socket, urgent!!!

    The pins on ICs are supposed to be soldered to a pcb. If you know how to solder properly then the IC will be fine.
  3. audioguru2

    Best of 30 LM3886 Application

    The datasheet and application notes from National Semi about their LM3886 are in English.
  4. audioguru2

    LM317 Variable power supply

  5. audioguru2

    Best of 30 LM3886 Application

    I didn't install version 3.50 yet because my pc extracts RAR files somehow just by right-clicking on them. I think the version 2.90 is doing it.
  6. audioguru2

    Best of 30 LM3886 Application

    I unzipped WinRAR version 3.50 and it still requires payment after 40 days.
  7. audioguru2

    Best of 30 LM3886 Application

    I couldn't find WinRAR in the first few pages of General because today this site loads very slowly or "hangs". This site's Search also couldn't find it. My WinRAR is the "2.90 32-bit console version" and is a demo for only 40 days, then I must pay the author in Finland to register and use it. I...
  8. audioguru2

    I need Help

    Why did you select such a high frequency? Not many parts work so high and I can't even think that high. You might cook yourself with those microwaves. ;D
  9. audioguru2

    Best of 30 LM3886 Application

    I find RAR files frustrating. If I try to extract using Win-RAR then a popup wants me to pay for it. When I extract the files (how?) by right-clicking, then this file opens into another 34 RAR files that must be individually extracted.
  10. audioguru2

    350w Studio Anfi Full Proje

    There are many things to consider when substituting power transistors: Voltage, current, power dissipation, frequency response, etc.
  11. audioguru2

    L298n IC socket, urgent!!!

    An IC socket has a max current rating of only a few milli-amps. This power driver has an output current that is way too high for a socket.
  12. audioguru2

    LM317 Variable power supply

    I also made a variable supply with an LM317 IC. Its regulation is extremely good and its output doesn't have any ripple.
  13. audioguru2

    350w Studio Anfi Full Proje

    350W into 4 ohms is a peak current of 13.3A. 200W into 8 ohms is a peak current of 7.1A. If used to play music then it won't be continuously operating at full output. So a transformer rated for half the rated power is fine. 100VA for an 8 ohm speaker or 175VA for a 4 ohm speaker.
  14. audioguru2

    Electronic parasite zappers

    Hey Steven, What kind of parasites do you have down under? Big kangaroos or wallabees chewing on your leg? Aliens from a UFO? Here we have mosquitoes sometimes and just a swat gets rid of them. ;D
  15. audioguru2

    shake light

    Hi Ante, That is a cranked torch without a crank. Do you just twist the shaft back and forth about 180 degrees?
  16. audioguru2

    Newb Question: 12v-80ma transistor switch

    A transistor is turned on with base current through the base resistor. With an 80mA load, a 2N4403 PNP or 2N4401 NPN transistor has a min current gain of 100, but even more base current is needed to saturate it, so 11.3V across the 10k base resistor results in a base current of 1.13mA which is...
  17. audioguru2

    Newb Question: 12v-80ma transistor switch

    No, the 2N4403 is fine. The load dissipates 0.96W, not the transistor. The transistor dissipates a max of only 240mW for a moment when it has switched the relay halfway. It dissipates about only 117mW when driving the relay continuously as an emitter-follower and much less when saturated as a...
  18. audioguru2

    Newb Question: 12v-80ma transistor switch

    The circuit is designed for a PNP transistor. It needs to be changed into the other circuit for an NPN transistor. Then the value of the base resistor must be selected to match the current gain of the transistor. The input to the base resistor must be 0V and the supply voltage. A 12V relay needs...
  19. audioguru2

    Newb Question: 12v-80ma transistor switch

    The circuit will work with a 2N4403 PNP transistor only if the input signal goes 0V and +12V. If the input signal goes only to +5V then the relay will never turn off.
  20. audioguru2

    Newb Question: 12v-80ma transistor switch

    I think you have a circuit designed for a PNP transistor but you are using a TIP3055 which is an NPN transistor. Also, a PNP emitter-follower needs the supply voltage at its base to turn off.
Top