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  1. Audioguru

    How do I simulate a double throw, single pole, voltage controlled switch in LTSpice?

    A switch is simply a piece of wire or is nothing.
  2. Audioguru

    Transformer output puzzle for tube pre-amp project

    The article about the tubes preamp mentioned its 6% harmonic distortion. I made an amplifier with tubes about 55 years ago and an amplifier clinic measured 10% distortion until its tubes were replaced. The tube replacements needed to be done quite often. I replaced it with a solid state...
  3. Audioguru

    Boost Converter To Charge Laptop From Car Battery Problem

    I think the cheap (ebay?) "3A" boost converter is actually 0.3A but the dot is so small it cannot be seen. Please post a video of it smoking and burning.
  4. Audioguru

    Health Care is so damn expensive...

    When I had a heart attack in Canada I was not placed in a waiting list, I was treated immediately. Please keep politics, religion and race away from this forum.
  5. Audioguru

    Newbie question about LEDs in Series/Parallel

    Nobody makes an LED with a voltage that is 2.0V, they have a range of voltage from 1.8V to 2.2V for a red LED. Some are 1.8V, some are 2.2V and some are in between. You get whatever is random. If you put three 1.8V LEDs ((they use 5.4V) to a new 6V battery then they will instantly burn out...
  6. Audioguru

    Choosing resistor value

    The maximum allowed current into the IC is 250mA. You do not use a resistor to reduce the current, instead you do not overload the IC. If the IC has no load then its current is only a few mA. The battery in a car can supply 400A to the starter motor when it is very cold. But the clock in the...
  7. Audioguru

    Transformer output puzzle for tube pre-amp project

    Phono? Tubes? Why?
  8. Audioguru

    How can i add a trigger to this circuit to make it not electrocute the user?

    The LEDs are not shorted to the 9V battery, they are driven with a fairly low current CD4017 IC. The Texas Instruments datasheet for a CD4017 shows a typical output current of 20mA into a dead short or 17mA into a 3.5V LED. But the max allowed dissipation in an output transistor is 100mW which...
  9. Audioguru

    Boost Converter To Charge Laptop From Car Battery Problem

    The label shows a 19.5VDC/2.31A adapter. It says 45W (19.5V X 2.31A) so the power and current must be when the battery is dead. Your ammeter has some resistance that reduces the current reading. Either the boost converter cannot produce its rated 3A output without burning or its output voltage...
  10. Audioguru

    Health Care is so damn expensive...

    I notice that the patients in the emergency department of hospitals and medical clinics are immigrants and refugees having their first cold or bruise. Many of them are crippled due to poor nutrition in the country they come from. They have contributed little if anything to the health care system...
  11. Audioguru

    Interfacing two powers

    Why don't you understand that when you press the switch then NO CURRENT goes through the darlington transistor, it goes through the switch instead. You can press the switch for hundreds of years and the darlington transistor just sits there with no current and no voltage except for the small...
  12. Audioguru

    Current limiting resistor power rating question

    My cheap Chinese flashlight has 3 AAA "Super Heavy Duty" carbon-zinc cells overloaded with 24 white LEDs in parallel. No current-limiting resistor was used because the cheap battery is awful. I replaced the cells with modern Western-made alkaline cells and WOW, the brightness is MUCH MORE. I...
  13. Audioguru

    Health Care is so damn expensive...

    I am glad that Canada is democratic and is not communist. North Korea is communist and life for most people there is miserable.
  14. Audioguru

    Blue Wire Laptop Charger.. Help!

    The laptop or its battery has either a circuit to measure charging current then feed a signal on the blue wire to reduce the charger current or the blue wire connects to a thermistor in the battery that feeds the charger to tell it to reduce the current because the battery is getting too hot...
  15. Audioguru

    Interfacing two powers

    The datasheet for the TIP125 shows a typical collector-emitter saturation voltage drop of 1V when its collector current is about 1.3A and its base current is about 5.2mA. Your 330 ohm base resistor causes a much higher base current then maybe your collector current is 4A. It is normal for the...
  16. Audioguru

    Health Care is so damn expensive...

    I am in Canada. A ling time ago I had my appendix and a broken arm fixed for free. I had two hernias repaired for free. I had cataracts surgery but I selected Improved lenses in my eyes (I paid a couple thousand dollars) which are much better than the older free ones. I had a heart attack...
  17. Audioguru

    Interfacing two powers

    If your circuit has a 4A load then your schematic posted here should not show a 7mA load.
  18. Audioguru

    Solar panel no amperage

    The cheap Chinese solar panels on my solar garden lights stopped working because the plastic covers got sunburned. I polished the covers and put a clear UV-resistant coating on them and now they work again. Modern cheap Chinese solar panels have a glass cover that lasts forever but they failed...
  19. Audioguru

    Working of a JK Flip-Flop. Help needed with the circuit.

    He is playing with an old fashioned TTL 74LS76.
  20. Audioguru

    Building a comparator

    You need to learn about charging a Lithium battery. 8.4V is two fully charged lithium cells. The charger is supposed to be a balanced charger so that one cell is never over-charged. A balanced charger monitors the voltage or each cell and bypasses current around the cell that is detected to be...
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