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  1. Audioguru

    Help needed! Voltage related -Vs +5v ?

    When you change the supply voltage from plus and minus 22V to plus and minus 12V then you also must change the divider. In addition to the IC being destroyed when the supply polarities were backwards, the electrolytic capacitors also might be destroyed.
  2. Audioguru

    Light therapy device

    Your LED Wizard does not know that the forward voltage is a range of voltages then its calculated resistor value is only for "typical" LEDs that you cannot buy unless you buy thousands of them, test them all and hope you get 40 typical ones. Maybe you should buy 40 LEDs, test them all then...
  3. Audioguru

    Light therapy device

    Philips produces products that are bought by everybody like lighting products. They also make extremely expensive medical equipment. But everybody does not buy IR LED products and the medical equipment uses x-rays or ordinary heating, not IR energy.
  4. Audioguru

    Help needed! Voltage related -Vs +5v ?

    There is no +5V. Instead it is actually -12V +5V= +7V on pin 3 for it to play. Then it is -12V when it is in standby and is muted.
  5. Audioguru

    LM358 to make FM Audio Receiver

    Since this is your school assignment then you should learn about the basics of electronics and do the assignment yourself. I would never use a lousy old LM358 for audio. With a properly designed pcb then an LM386 power amplifier IC circuit is inexpensive, easy to make and sounds pretty good but...
  6. Audioguru

    Light therapy device

    Philips Luxeon LEDs in a 4-pins Superflux package are made in all colors but not IR.
  7. Audioguru

    Hard-wiring David Clark headset station to ICOM A110 radio

    No technical details or schematics for the radios, the headphones, the stations or the cables. Should we guess about them??
  8. Audioguru

    Light therapy device

    One of the two pins on an LED carries heat to the printed wiring. At 20mA then a 5mm IR LED will not overheat because its heat is 20mA x 1.2V= only 24mW. My 4-pins LEDs were 2.6V at 60mA each which is 156mW.
  9. Audioguru

    Light therapy device

    I think your 80 IR LEDs will blind you because you cannot see IR heat energy. Your retinas will get cooked well done. I made a night light with 36 red LEDs crowded together and boy oh boy did they get hot.
  10. Audioguru

    LM358 to make FM Audio Receiver

    You made many errors:
  11. Audioguru

    Connecting Pavlok to a BacTrack SKYN alcohol intake monitor?

    I have seen a guy's wife slap him if he has a drink. Maybe she could use a zapper instead.
  12. Audioguru

    Guidance

    I am in Canada and I would not ask about job opportunities in India which is completely different. I think this guy should ask in India, not here.
  13. Audioguru

    Analog Circuit Outputs

    Kapp simply explained the simple basics of electricity (Ohm's Law) that was not taught in India.
  14. Audioguru

    Adjustable timer circuit

    You should add a 1k resistor in series with the pot to prevent burning out the transistor at pin 7 if the pot is turned down to zero. I think your hard to see sketch shows it backwards. It is clearly shown on its datasheet.
  15. Audioguru

    Self-Charging Phone Case

    It is called a "power bank" and has a 3.8V Lithium rechargeable battery in it. Its 5V USB input has a charger circuit to feed its Lithium battery and its USB output has a circuit to stepup the voltage from its battery to 5V for charging a phone. It also has a circuit to shut it off when its...
  16. Audioguru

    MC34071

    No. The MC3407x is better than the MC3317x but the MC3317x is an improved LM358/LM324. No again. ON Semi say the MC34071 is in production but its old through-holes case is obsolete. Digikey has thousands in stock with the surface-mount package. Using only one of the opamps is fine. Thousands...
  17. Audioguru

    What battery do I need for these LED bulbs?

    An LED is a diode. It must be connected with a current-limiting device (usually a properly calculated resistor) and with the correct polarity. Maybe the LEDs from ebay are cheap Chinese fakes but a few of them might work. Please post a schematic of your test showing: 1) Battery voltage, size and...
  18. Audioguru

    Fm receiver circuit .

    R5 adds DC negative feedback to stabilize the operation of T2 since its DC gain could be high or low. C6 bypasses R5 so that T2 has a very high AC gain and lots or distortion.
  19. Audioguru

    MC34071

    Why don't you look at the datasheet for the MC34071 and MC34072? The MC34072 has two opamps in it and if both are used in that circuit then the IC will get very hot and might be damaged.
  20. Audioguru

    LED Lights help

    I think there is too much rice in the wires on those cheap Chinese LED strings. In things that I make, my wires are pure copper with no added rice. I thoroughly test everything I make, the Chinese designers didn't.
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