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  1. BobK

    Help to solve Operational amplifier

    For an ideal op amp: Distorted: The output signal is larger than the supply voltage. Inverted: This can happen on real op amps, but not on an ideal op amp. Bob
  2. BobK

    Type of wires

    Yep, that is what 16pF / foot means. Bob
  3. BobK

    Question about Li-ion batteries

    I have some supposed 3600mAH cells. I measured them, with a light draw (20mA LED) at about 2000mAH. Bob
  4. BobK

    Zener diode as volt dropping resistor??

    Using a Zener diode will consume exactly the same power as using a resistor when the same voltage drop is achieved at the same current. Bob
  5. BobK

    Help to solve Operational amplifier

    You have computed the power in a square wave. For the RMS power of a sine wave, divide the voltage by sqrt(2) which divides the power by 2. 6.25W Bob
  6. BobK

    Pickit 2 - won't write.

    Take out the returns after the calls to Delay. A return is used at the end of the function that you call. In this case a retlw. Bob
  7. BobK

    Headphone amplifier ground issue

    That is likely a bridged amplifier, neither of the speaker terminals is at ground, so they cannot be connected together. And it is WAY overkill for a headphone amp unless you want to shake your brain loose. Headphone amps are typically under 1W. Bob
  8. BobK

    Electric guitar wiring trouble

    Yep, I was blind! Bob
  9. BobK

    Electric guitar wiring trouble

    Am I blind or what? I see only one wire coming from the pickup. Bob
  10. BobK

    Simple LC Oscillator

    Here is a practical circuit for a Colpitts's oscillator. The C in the LC is computed as C1 and C2 in series, in this case 50n. The output comes from the collector of Q1.
  11. BobK

    Question about Li-ion batteries

    He used old Li Ion batteries from laptops? And then charged $90K for the car? Brilliant! Bob
  12. BobK

    Power consumptions of electronic items.

    Reduce the current or the voltage. Bob
  13. BobK

    Aftermarket Radio LCD Swap ?

    If all LCD screens operated the same way, you would be fine. Except that, if the resolutions were different you would either see not all of the display or it would be in one corner with the rest left blank. Bob
  14. BobK

    Overheat of electronic items

    Stop operating them at or above max ratings. Don't operate in an environment that is 50C. Bob
  15. BobK

    Pickit 2 - won't write.

    Put a delay after turning the LEDs on and one after turning them off, about 1/4 second or so, and you will see them blink. Bob
  16. BobK

    Pickit 2 - won't write.

    Your PIC is running just fine. You are blinking the LEDs at a rate way to fast to see them blink, thus they look like they are on all the time. The one connected to pin 4 will not work because the pin assigned to MCLR cannot be made an output. Not sure why the RA5 one is not working. Check...
  17. BobK

    motor controller for electric bike project

    Since a bike is not driven backwards, you need only a single switching transistor (MOSFET) and something to generate a PWM signal. A NE555 timer is the simplest. Bob
  18. BobK

    Boost converter with no controller

    For a boost converter, a certain amount of energy is loaded into the output capacitor during each ON part of the cycle and a certain amount is drained from the capacitor during the OFF part of the cycle. For a given constant load, these will balance at some voltage. Change the load and the...
  19. BobK

    18650 stays @ 4.15 volts

    Normal float voltage is 4.2V. How accurate is the meter you are using to measure it? 4.15 might actually be fully charged if the meter is off by only a little more than 1%. Bob
  20. BobK

    Op Amp Circuit Noise

    Okay, What is the supply voltage to the op amp (U1) in this circuit?
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