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  1. Audioguru

    LED Driver Wattage Question

    There must be a lot of people who are happy paying little for ebay junk.
  2. Audioguru

    LED Driver Wattage Question

    The ad for a cheap no-name-brand product can say anything. Do you trust the lies?
  3. Audioguru

    Noob question

    I think a value of "103pF" is fishy. It is probably 10,000pF or 10nF (0.01μF).
  4. Audioguru

    LED Christmas lights gone dim

    The LED string that I found had corrosion in a few spots where the LED wires simply touched the string wires making a poor connection. At least one LED had one of its wires severely corroded and ready to fall off. That would cause dimming before complete failure.
  5. Audioguru

    Need help !! LDR night light

    Select a more sensitive LDR, they are all different. Mine have sensitivities of 10 to 1. Select a transistor with a higher hFE at high currents like a 2N4401 or a darlington transistor then the base resistor value can be higher. Use a resistor in series with the LEDs to prevent them from burning...
  6. Audioguru

    LED Christmas lights gone dim

    I found a string of Christmas tree LED lights that were thrown away. Of course they did not work. I unscrewed the cover over an LED and the LED fell out. Its leads were not connected but were simply touching the wires of the string. Some of the LEDs have their leads and/or the string wires...
  7. Audioguru

    Time to start building grow lights!

    Have you ever seen a stoned pothead try to drive his car up a tree or down a river? Soon you will see that and other dumb things (jump or push somebody off a balcony?).
  8. Audioguru

    Want to increase brightness of LED headlight

    No and no. If you add a smoothing capacitor then the IC will need extra output current to charge it. You cannot parallel ICs because there is no way to sync their oscillators. Use a separate circuit for each LED if one IC cannot drive enough current for two parallel LEDs. It has a 6V battery...
  9. Audioguru

    Want to increase brightness of LED headlight

    The circuit converts a low voltage to a higher voltage and the power must not change except to make up for loss of efficiency. If the LEDs need 3.6V at 80mA but the battery is only 2.4V then the battery current is 3.6/2.4= 1.5 times higher plus about 20% more for losses which is a total battery...
  10. Audioguru

    Want to increase brightness of LED headlight

    The headlight has only two rechargeable AAA cells for a maximum of 2.8V that drops to about 1.6V during their discharge so a voltage boosting circuit is needed.
  11. Audioguru

    Want to increase brightness of LED headlight

    The current curves in the datasheet are for the peak current, but our vision sees the average current that is much lower because the LEDs are pulsed on and off. That is why a solar garden light is rather dim, the pulses are PWM dimming.
  12. Audioguru

    Problem with diy audio mixer - high frequency sound

    An opamp can be simply biased so that it does not need a negative supply voltage. A single opamp is usually used as a mixer, the circuit uses 4 opamps because each of its inputs is amplified. Some opamps will operate from a 5V USB supply.
  13. Audioguru

    Problem with diy audio mixer - high frequency sound

    The capacitance of your messy wires might cause oscillation of the circuit near them.
  14. Audioguru

    Want to increase brightness of LED headlight

    A SMD inductor might have a low maximum current then it will saturate. The Ni-MH Battery Applications Manual from Energizer shows that a cell provides little power when discharged below about 0.9V per cell. The cell is damaged only when it is the lowest capacity one in series with a mismatched...
  15. Audioguru

    5v from 12v is this viable?

    The Little Gem MII project does not say R1, R2 etc. The Jfet (it is not a Mosfet) is a follower with a gain of 1. The source resistor should be 10k ohms to provide a suitable bias voltage. What is R1? If R1 is the input 1.5M resistor then it is not a filter, it biases the gate of the Jfet at 0V...
  16. Audioguru

    Want to increase brightness of LED headlight

    The low current solar garden light ICs are made for a single cell 1.25V input, not two cells that you have. The ZXSC380 has a wide input voltage range with a mean output current of about 18mA which might be fine, but the peak current is 65mA with a 2.8V fully charged battery that might zap the...
  17. Audioguru

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

    Both transformers have 40μH on one side and only 10μH on the other side of the center tap causing severe distortion instead of equal inductances on each side of the tap.
  18. Audioguru

    Problem with diy audio mixer - high frequency sound

    Please show the schematic and a photo of your simple audio mixer and what is connected to it.
  19. Audioguru

    LED Panel light with driver

    Amazon should not be allowed to sell wrong garbage like that. You should not buy cheap electrical products that are not CSA approved and might burn down your home.
  20. Audioguru

    Problem with diy audio mixer - high frequency sound

    A potentiometer plus a switch is not an audio mixer circuit. If you have a [real[/b] circuit then if it oscillates the frequency would be so high that you would not hear it. I think you have acoustical feedback howling where the microphone can hear the speaker and the sound goes around and...
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