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  1. Audioguru

    Problem in inverter circuit

    It is terribly discouraging for me to post on the website that originated that horrible circuit and say all its problems then have people asking about it many years later on other forums. Here is another horrible project from that website:
  2. Audioguru

    LTSPICE Help needed to make transformer coupled amplifier & push pull amplifier

    Why are you simulating an antique circuit? Philips made a similar transistor amplifier in 1955 (61 years ago) using a transformer:
  3. Audioguru

    LED Celling stay glow.Can I stop that?

    Neutral and Earth are supposed to be connected together. The light switch is supposed to connect and disconnect the Line wire not the Neutral.
  4. Audioguru

    Problem in inverter circuit

    Like I said on EDAboard, that is a horrible circuit from www.aaroncake.net that does not work because it is too simple: 1) The capacitors have backwards polarity so they blow up! 2) The transistors emitter-base junctions have reverse biased avalanche breakdown. Here are my fixes for the two...
  5. Audioguru

    LED Celling stay glow.Can I stop that?

    The phosphor in my compact fluorescent light bulbs glow for about 1 minute after being switched off. Maybe the LEDs in this lamp have a new phosphor that glows for awhile?
  6. Audioguru

    Solar Street Light

    The cheap ($1.00) Chinese solar garden lights I bought from Walmart lasted about 2 months because the solar cells were plastic and got sunburned and the Ni-cad batteries rusted away and leaked. But by golly they improved them. The new solar cells are glass and the new Ni-MH batteries do not...
  7. Audioguru

    LED Celling stay glow.Can I stop that?

    The light switch is supposed to disconnect the L wire when the switch is turned off. If it doesn't then the switch should be replaced.
  8. Audioguru

    Solar Street Light

    Old streetlights used a light dependant resistor that failed when it got old, dirty, or sunburned. Then they used the solar panel to switch the light on or off. Today my streetlights have an RF modem switch them. They are not solar because their LEDs draw a small current from cheap electricity.
  9. Audioguru

    Headphones from amp speaker wires

    You have the wrong kind of jack. Use this kind of jack connected like this:
  10. Audioguru

    Hooking up LED lights turn on like dome lights

    LEDs are pretty bright with 20mA each. For 30 of them in parallel you need 600mA but half (300mA) might be fine. Ohms Law calculates the resistor value to deliver 300mA from 13.8V in a car down to about 3.2V for white LEDs (the 4.5V battery probably drops to 3.2V when it is overloaded with 60...
  11. Audioguru

    LED Celling stay glow.Can I stop that?

    It already is a normal lamp. Its electrical input has 3 wires like most lamps. The wires are ground, neutral and line. Your switch is supposed to connect and disconnect the line wire but you probably have the switch or the lamp connected wrong.
  12. Audioguru

    Cant get a voltage reading off an working AC/AC Adaptor with a multi meter ?

    If you used the wrong adapter to power them all then probably now they are all damaged.
  13. Audioguru

    Headphones from amp speaker wires

    You have a mono jack with tip and sleeve but don't you have stereo headphones that have tip, ring and sleeve?
  14. Audioguru

    5v from 12v is this viable?

    The Li'l Gem amplifier with two bridged LM386 amplifier ICs driving an 8 ohm speaker and a 9V supply draws about 250mA. The maximum from a 78L09 is only 100mA so you must use a larger 7809 with a little heatsink bolted to it. Its datasheet shows that it needs an input capacitor and an output...
  15. Audioguru

    Resistor

    When it has powered the smoke detector for 1 year the 9V alkaline battery in it measures close to 9V but its internal resistance has become so high that it cannot supply much current. The smoke detector blinks the LED every 10 minutes and during the blink it measures the battery voltage to see...
  16. Audioguru

    4020 divided outputs

    Sorry for the stereo current spikes.
  17. Audioguru

    4020 divided outputs

    Are the CD4020B ICs cheap fake Chinese ones from ebay? You should use a modern Cmos 555 called LMC555, TLC555 or ICM7555 because an ordinary old 555 draws a 400mA current spike each time its output switches that might be killing your battery voltage and your circuit is missing a supply...
  18. Audioguru

    Help building LED power supply

    The LEDs are probably driven from a voltage stepup circuit that limits the current. You cannot measure the LED voltage or current because it is pulsing on and off at a high frequency. 1.24V continuously is for an infrared LED that is invisible, 1.8V is for a red LED and 3.2V is for white, blue...
  19. Audioguru

    5v from 12v is this viable?

    When two amplifiers are bridged and feed an 8 ohm speaker then their output current and heating are doubled as if they are separate and each has a 4 ohm load. The little LM386 is designed to drive an 8 ohm speaker to 0.5W output. A car radio bridged amplifier produces 14W into 4 ohms, a huge...
  20. Audioguru

    Why don't I get a Sine wave?

    My very low distortion sinewave generator project uses a variable frequency squarewave oscillator clocking a CD4018 with 5 resistors on its outputs making a mixed waveform with 10 steps (shown in Don Lancaster's Cmos Cookbook). Then two switched capacitor Butterworth lowpass filter ICs in series...
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