Search results

  1. Hero999

    Identifying an obsolete Varo rectifier?

    Can you post  picture? I doubt you'll be able to find an exact replacement. It seems odd that it goes from L to N unless it's a bridge but it can't be otherwise it'd have four wires.
  2. Hero999

    need a project idea on noise sensing

    I designed a simple cirucit that will do this and posted it over on Electrotech Online but don't expect any help from me over there because the idiot administrator banned me for disagreeing with him. Fortunatley it can be found on the second Google hit...
  3. Hero999

    capacitor conversion chart

    No one taught me how to convert, I figured it out myself. Look at the relationship between the numbers on the chart and you shoud be able to figure it out yourself and if you can't  then sorry you'll never make an engineer.
  4. Hero999

    My ZVS Flyback Driver with pcb

    The 20k resistor is really 27k. in Steven's schematic.
  5. Hero999

    capacitor conversion chart

    What a waste of time. I can convert the capacitor code to pF, nF and uF faster in my head than using that silly chart.
  6. Hero999

    TT2076

    Can you speak Japanese? http://www.ges.cz/sheets/t/tt2076.pdf
  7. Hero999

    LM338 Power Suply Current Regulator

    The junction is the actual piece of silicon inside the case. I'd recommend using an old Pentium 3 CPU cooler as the heat sink because it will have a thermal resistance of under 0.5
  8. Hero999

    Darkroom timer V2.0A project question ????? (Solved)

    I generally try to remove as much flux as possible because it looks better and I've heard stories about it attacking copper in moist environments.
  9. Hero999

    questions about FM Superhetrodyne Receiver

    It could be either but normally the local oscillator is higher not lower.
  10. Hero999

    computer speakers

    No, frequency response is entirely down to the speakers and even the enclosures, modern amplifiers go well below 20Hz to well above 20kHz. Cheap and good sound quality, especially decent bass response are incomparable requirements.
  11. Hero999

    Equivalent to BF494 and BF495?

    PNP is basically the opposite to NPN, the collector and base voltage is negative with respect to the emitter and the transistor turns on when the base voltage is 0.6V below the emitter. The voltage is a maximum rating. Ic is the maximum current rating. The cut-off currents are basically the...
  12. Hero999

    computer speakers

    Where's the error? That graph looks pretty standard to me. The one you posted is fuzzy because it's ripped from the PDF, is low resolution and has probably gone though JPG compression, the one on the Visaton website (posted above) is more clear. RS Components seem to be a bit cheaper for...
  13. Hero999

    LM338 Power Suply Current Regulator

    Maybe audioguru made a mistake, I make it 43W per transistor. It's not 5A shared between the transistors, remember 0.2A goes through the regulator. If the voltage across the emitter resistors is 0.125V. The voltage across the transistors is 31-0.125 = 30.875V The current through all the...
  14. Hero999

    computer speakers

    The amplifier is not the only problem, the cheap speaker drivers and enclosures make it sound poor. You might be able to buy some great sounding speakers for that, the trouble is cheap speakers don't come with any real frequency response specifications and have a grossly exaggerated power...
  15. Hero999

    LM338 Power Suply Current Regulator

    No, the power dissipation is equal to the voltage across the regulator multiplied by the current through it.
  16. Hero999

    Battery backup for car dvd player

    I doubt a little 9V battery will be able to supply the current required for a DVD player even for short periods of time. You can get small sealed lead acid batteries which are non-spillable and pretty safe if mounted in a child proof container.
  17. Hero999

    Battery backup for car dvd player

    The simplest solution is to connect the DVD player directly to the battery which is permanently live. Another option is to connect a small 12V sealed lead acid battery in parallel with the cigarette lighter socket so it remains powered at all times. The battery should have a fuse in series with...
  18. Hero999

    TIP107

    Turn of the capslock. Any transistor will burn out, if its maximum power or current specification is exceeded but I don't know in your case because you haven't posted a schematic.
  19. Hero999

    Evaluating total energy usage from just DC voltage and current

    An offset of 10mV or and error of 10mV? An error of 10mV over 200V is 0.005% tolerance which is pretty unrealistic, I don't think I've seen a multimeter that good and if you can buy a meter that accurate it certainly won't be cheap. An offset of 10mV is more realistic but you're better off...
  20. Hero999

    5 LED ring oscillator sequencer.

    Here's another circuit I've built recently, it's nothing new, a ring oscillator connected to some LEDs so they flash sequentially. It can also be used to make a traffic light sequence: red, red+amber, green, amber, red by connecting the LEDs up differently. Attached is the schematic and a...
Top