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  1. Audioguru

    Battery advice for size and weight sensitive project

    Beware of Hobby King. Some of their Li-Po batteries are very cheap and seem to be missing any quality control or even any testing to see if a battery works. On airplane forums people say some of the Hobby King Li-Po batteries work fine, but only for 10 times instead of for hundreds of times like...
  2. Audioguru

    Weapon worries...

    If a Cmos Schmitt Trigger gate or inverter is not available then an oscillator made with 2 Cmos gates or inverters works fine, I have used hundreds of them. I have never used a 3 gates oscillator. I have the 43 years old Fairchild applications note #118 that says "3 gates will always oscillate"...
  3. Audioguru

    240VAC Transformer based 12 VDC PSU - Problem

    Years ago I used tantalum capacitors because they were small. Every single one of them blew up and disappeared. They were Name Brand European ones, not the junk we get from Asia today.
  4. Audioguru

    240VAC Transformer based 12 VDC PSU - Problem

    You are correct, I was wrong. The maximum input to output is 18V so the maximum allowed input is 30V. You should add a 10uF tantalum capacitor to the output.
  5. Audioguru

    Questions battery AA and AAA and battery charger

    I was wondering why you want to preserve things. Are you going to jail for many years? The circuit in the Sony charger is very simple. It will probably still work when you are released from jail. The electricity in most countries has no surges. If yours has surges then use a surge limiter thing...
  6. Audioguru

    240VAC Transformer based 12 VDC PSU - Problem

    Why not look at the datasheet for the regulator: 1) The DC input you have is very close to its maximum allowed voltage and maybe your electricity voltage is a little higher today than before, mine is. 2) The datasheet says that a 10uF tantalum capacitor must be added to the output to prevent...
  7. Audioguru

    Questions battery AA and AAA and battery charger

    The circuit in the Sony Cycle Energy charger is very simple so it will probably last for many years in a drawer. All Chinese "super-heavy-duty" batteries leak even before they are sold. All my Duracell alkaline batteries leaked. But none of my Energizer alkaline batteries leaked and they are...
  8. Audioguru

    Battery advice for size and weight sensitive project

    A lithium-Polymer (Li-PO) battery is the same as a Lithium-Ion except it is smaller and lighter because its case is a plastic film instead of metal. Electric model airplanes and quad-copters (small drones) use a single cell that is 3V when dead to 4.2V when fully charged. Hobby stores have them...
  9. Audioguru

    Audio Generator vs. Signal Generator...

    Repair job? Where?
  10. Audioguru

    Weapon worries...

    No, an ordinary CD4011 will not oscillate in this circuit because it has NO hysteresis. Its output would simply stay at about half the supply voltage due to the negative feedback provided by the resistor. Here are Cmos oscillators (squarewave outputs):
  11. Audioguru

    Weapon worries...

    The schematic is WRONG. It shows ordinary CD4011 NAND gates that will not oscillate in that circuit, not CD4093 Schmitt Trigger NAND gates
  12. Audioguru

    Questions battery AA and AAA and battery charger

    The operating instructions for the Sony Cycle Energy Ni-MH battery charger says that it simply has a 7 hours timer, it does not measure when a battery is fully charged. Therefore it can over-charge and damage batteries that are already charged or are partially charged. They recommend completely...
  13. Audioguru

    Audio Generator vs. Signal Generator...

    My first project was a audio amplifier kit that used vacuum tubes that I fed from a vinyl records turntable. My second electronic project was an FM tuner kit (also using vacuum tubes) and it worked perfectly. My third project was a stereo multiplex adapter kit for the FM tuner. For all of them I...
  14. Audioguru

    Motor speed help

    We might not find anybody who remembers how it was done 55 years ago without integrated circuits. Can your teacher remember how it was done? Why doesn't your teacher teach how it is done today?
  15. Audioguru

    P channel mosfet

    The Mosfet and all the other parts can be replaced with a piece of wire because the light is always turned on.
  16. Audioguru

    Modifying a led strip circuit

    I forgot about Banggood crap. Google sends me a Banggood ad every time I use Google. I found strings of about 50 blue LEDs and 100 white LEDs in Christmas tree sets. The blue string was thrown away because it did not work. The wires on the LEDs were not connected to the wiring, they were simply...
  17. Audioguru

    Audio Generator vs. Signal Generator...

    What is there in the audio part of a radio to adjust using an audio generator? Usually an audio circuit is designed to work correctly. Maybe the kit is showing you how to fiddle with adjustments to make it work correctly?[/B]
  18. Audioguru

    Modifying a led strip circuit

    I did not know that Indian junk is sold in England. Here in Canada there is an Indian surplus electronic parts store Sayal that sells some good stuff and some garbage. I think ebay, Amazon and Ali sell lots of garbage. Here are many good LED strips...
  19. Audioguru

    Modifying a led strip circuit

    The LEDs are probably connected all in series for each of the 4 wires then if there are 25 white 3V LEDs they need 75V. LED strips in The West use 3 LEDs in series and in series with a resistor and many groups like this all powered from 12VDC. The guy in India says, "The LEDs in each string are...
  20. Audioguru

    Modifying a led strip circuit

    Dispose the dangerous junk and buy a safe 12VDC LED strip from The West. I saw a local store with high voltage neon lights in the window. The extremely dangerous high voltage transformer was laying where anybody could touch its connections. The store manager could not speeky zee Engrish so I...
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