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  1. audioguru2

    R-L-C AND HARMONICS

    Hi Alun, My tubes are 48" which is about 1.5m. The ballast is just a coil with a couple of filament windings, not an autotransfomer and it works fine on 120VAC.
  2. audioguru2

    Hum in the incoming signal

    Hi 4-1000A, I thought if the generator used exactly the same wires as the mains, then there wouldn't be a problem since the mains works well with no coupling and no ground loop. Maybe the generator is grounded at its location, far from the mains ground. Inside a grounded metel cabinet, I...
  3. audioguru2

    LM317 Variable power supply

    Hi Autir, I also built my LM317 variable supply on stripboard. I had the load connected to the heatsink tab, with a terminal screwed on with the same bolt that attaches it to the heatsink, then connected the current-setting resistor to the output pin without any load current in it. Then the...
  4. audioguru2

    Inverter Circuit 12V DC to 230VAC Sine Wave

    Hi Ante, I was looking and looking at that 3kVA schematic and wondering, "how do dey do dat?" and looking for a way it can make a "stepped" sine wave. Then I realised that it simply pauses between its pulses like this:
  5. audioguru2

    R-L-C AND HARMONICS

    Hi Alun, Electricity is cheap over here because it "comes out of the ground" at Niagara Falls. So we don't bother correcting the power factor on little things. Our florescent ballasts are just a big inductor with a filament winding for each end of the tube. They don't use a starter circuit, the...
  6. audioguru2

    in car light.

    Hi Policeman, It shouldn't be too difficult if you build it in stages: 1) Make a Cmos 555 oscillator with a TLC555 or LMC555 IC. 2) Make 2 sequencers with two CD4017 ICs. 3) Connect the oscillator to the sequencers and add up to ten 1N4148 or 1N4002 diodes for pulsing outputs. 4) Add two IRL540...
  7. audioguru2

    in car light.

    Hi slim US cop, Ultra-bright LEDs are about 3.5V, and two could be wired in series and in series with a current-limiting resistor. Figure a current of 20mA so the resistor would be about 330 ohms. A CD4017 sequencer IC can blink a circuit if you connect diodes to its outputs. All the even...
  8. audioguru2

    in car light.

    Hi Snafu-Crunch, Welcome to our forum. ;D In Canada, cops are going around giving tickets to people with blue lights on their cars. Blue is reserved for snow-plows, even in summer. Your cops might be ticketing themselves! ;D ;D Police cars usually use strobe-lights on their cars. A strobe-light...
  9. audioguru2

    Electronic advise please ???

    I couldn't. I cut my finger when I was tying up my roses. :'( Can't you make an automatic button? ???
  10. audioguru2

    Polyester cap?

    Hi Zac, I tried to sell my blinking projects at my city's "midnight street party" for 20 bucks. There were Chinese people there selling by the thousands brightly blinking buttons similar to my big ones for only 2 bucks! They used surface mount parts and a main microcontroller IC. Their small...
  11. audioguru2

    Electronic advise please ???

    Hi Staigen, I pressed your start button many times, but nothing happened. :'( :'(
  12. audioguru2

    theory on fridge door alarm

    The datasheet for the project's CD4060 oscillator/counter IC explains pretty well how it works: http://www.datasheetarchive.com/semiconductors/download.php?Datasheet=533773
  13. audioguru2

    Electronic advise please ???

    Using a microcontroller that you have programmed yourself would be the easiest way to perform the task. The microcontroller could even press the start button for you. Using separate parts it would need an oscillator, an up-down counter, many gates and a few flip-flops. ;D
  14. audioguru2

    Hum in the incoming signal

    If the generator is grounded to exactly the same point as the mains, and used the same wires to your equipment, then the problem of hum shouldn't exist.
  15. audioguru2

    Inverter Circuit 12V DC to 230VAC Sine Wave

    What was wrong with its output? ??? You can't load it when using the flimsy wiring and contacts of a breadboard.
  16. audioguru2

    Electronic Stethoscope

    The breadboard's wiring would be shielded if it is inside a metal box that is connected to the circuit's ground. Without shielding, the wiring would pickup mains hum, static from appliances and local AM radio stations.
  17. audioguru2

    R-L-C AND HARMONICS

    The ballast of a florescent lamp is a current-limiting inductor. An inductor has inductive reactance to AC which is like a resistor without loss (without much heating). I haven't seen a capacitor nor resistor in a florescent light's ballast. Without a capacitor with the inductor then it doesn't...
  18. audioguru2

    LM317 Variable power supply

    Hi Autir, If you have it wired so that load current travels through a wire or pcb trace to which R2  (the pot) is connected to ground and the resistance of the wire or trace develops a voltage across it, then the regulation is much poorer. National Semi explanes a similar problem that is caused...
  19. audioguru2

    R-L-C AND HARMONICS

    Hi Nalen, Please think about it. Parallel Resonance. Don't you think that a parallel resonant circuit is supposed to be a high resistance at resonance? What happens to it and its attenuation of harmonics if it had a low resistance across it? Series Resonance. Don't you think that a series...
  20. audioguru2

    LM317 Variable power supply

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