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  1. Audioguru

    Multisim Circuit

    Maybe Multisim does not like to see battery V3, R3 and LED3 shorted by S1 and the parts to the right of S3 that are doing nothing. Remove the useless parts.
  2. Audioguru

    Garden Lights, Disable the multi-function.

    What is the problem? The juice runs out on the panel every evening then the rechargeable battery is charged and powers the thing all night long. Its power might fail after a few days of bad weather. Maybe you do not have it in a location that has direct sunshine all day long? Maybe the solar...
  3. Audioguru

    Transistor voltage measurement

    We do not have a clue about your transistor circuit because you did not attach its schematic to this thread. The schematic will show the part number of the transistor, the supply voltage and the resistor values. Something (maybe a switch?) on the schematic will turn the transistor on and turn it...
  4. Audioguru

    Transistor voltage measurement

    Vbc is the voltage from the base to the collector. Vbe is the voltage from the base to the emitter. Vce is the voltage from the collector to the emitter.
  5. Audioguru

    rewiring an emergency light with tubes for LED strips

    An F6 tube light is a fluorescent light that uses a high voltage that is completely different to an LED low voltage light. Learn about LEDs then make a new circuit for them.
  6. Audioguru

    LM13700 sim in TINA-TI help!

    The squarewave has offset voltage because it comes from the emitter of the output darlington that has no negative feedback. The darlington has two base-emitter voltage drops.
  7. Audioguru

    LED headlight build

    I do not know where you found 35W and 55W. I think their brightness look almost the same. Our vision's sensitivity to brightness is logarithmic (then we can see in moonlight and in sunlight) so 10 times the lumens look twice as bright. The datasheets for many LEDs show that the lumens increase...
  8. Audioguru

    LM13700 sim in TINA-TI help!

    If The old LM13700 IC is still available then why not build and test the circuit instead or trying to simulate it?
  9. Audioguru

    LED headlight build

    Here in Canada there are laws about tampering with lighting on motor vehicles so that the light is not too bright, too dim, too wide angle, too narrow angle or the wrong color. Your idea might have more than one of these hazards. You talk about Watts but you do not mention brightness.
  10. Audioguru

    Light therapy device

    A power supply with more than one voltage will almost always be accidently set to the wrong voltage which will blow up what it is powering.
  11. Audioguru

    74HC390 table of pin connections?

    Did you look at the datasheet of the SN74HC390? Oh, Texas Instruments say it is obsolete do not show its datasheet.
  12. Audioguru

    Li Ion batt. pack

    I have heard that when a lithium battery is discharged too low then the lithium ions form plated Lithium metal. Then if the cell is normally charged it is shorted and explodes or catches on fire. A Lithium battery charger IC detects that a cell has been discharged too low then begins a test...
  13. Audioguru

    Time step too small in LTSpice

    Right click on "tran 50ms" then finish filling out what is needed. "Time to start saving data" should be 0ms for it to start and "Maximum timestep" can be 5ms. Increase the "Time to start saving data" time to see fewer cycles.
  14. Audioguru

    Simple Resistance Division

    My simulation shows the poorly biased transistors barely working and without enough output to be heard. When the circuit is biased properly then its output will be awful squarewaves (fuzz) with lots of signal level.
  15. Audioguru

    LM358 to make FM Audio Receiver

    Since you do not know the function of R2-R7 then you know nothing about transistors and you should take an electronics course in school.
  16. Audioguru

    Brake light flasher (555 - based) circuit works on breadboard, but not PCB

    Measure the voltage at pin 4 (reset pin) of the 555. The 5.1k resistor R4 to the positive supply should make it at the positive supply voltage to allow the 555 to cause the light to flash if the transistor is turned off or is removed. The voltage will be 1V or less to cause the 555 to be reset...
  17. Audioguru

    New apartment getting shocked on light switch screws.

    I think the thousands of volts from static electricity will easily arc over a resistor or tape rated for only hundreds of volts and ZAP you.
  18. Audioguru

    Simple Resistance Division

    Sorry, I made it hifi. I think "fuzz" is that you want severe distortion.
  19. Audioguru

    Simple Resistance Division

    Your transistors have no part number so we cannot look at their datasheet. Transistors have a wide range of hFE, the simple circuit will work only if you buy thousands of transistors and select ones with the hFE that will work in that simple circuit. You might not find any. A transistor usually...
  20. Audioguru

    New apartment getting shocked on light switch screws.

    Cold air (winter) contains much less humidity than warm air. Your shoes or slippers on carpet or your clothing develops static electricity and it builds up if the shoes, slippers or air does not conduct it away. Anti-static carpets are available.
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