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  1. BobK

    Reverse bench grinder

    Yes, just rotate the bench grinder by 180 degrees. Bob
  2. BobK

    nano coils

    Using DC, 0V. Bob
  3. BobK

    Equivalent Circuits

    It is worse when they do go where they shouldn’ t. Bob
  4. BobK

    Simple power supply that can be embedded in a wall socket

    At least in the U.S., there is no neutral line in the switch box. One is live and one is the other goes through the load to neutral. You cannot draw power from this arrangement. Don't know if it is the same where you are, but if there are only 2 wires, you are out of luck. That said. You...
  5. BobK

    Equivalent Circuits

    How do you figure that? Bob
  6. BobK

    Modifyling Electric Wheelchair Motor Control (H Bridge)

    You can buy a PWM controlled H-bridge quite cheaply. Assuming less then 40A, this one should do: https://www.ebay.com/itm/DC-40A-DC-Motor-Speed-Control-Reversible-PWM-Controller-12V-24V-36V-48V-2000W/173177079359?hash=item285228863f:g:9G8AAOSwmudaBFpO:sc:USPSFirstClass!01605!US!-1:rk:6:pf:0 Bob
  7. BobK

    Are these in parallel?

    Parallel components will always have the same voltage across them. Is that the case here? Bob
  8. BobK

    Transistor LED Circuit

    Thanks, now it makes some sense. All you need to do to cut the LEDs somewhere in the middle is add a new resistor. If you can show us an extreme closeup of the strip, we might even be able to tell you how to do it. Bob
  9. BobK

    Hi folks! I'm new here and don't understand JFETs

    Yep, the earth shakes when I am in town! Bob
  10. BobK

    Just a quick check of my circuit

    My keyboard does not do this if I understand you correctly. I can press and hold the a key, then press the b key and it will send a b. It is made by Logitech. Bob
  11. BobK

    Transistor LED Circuit

    It is time to tell us what it is you are trying to accomplish. Your descriptions so far leave much to be desired, you are describing a proposed solution when we don't know what the problem is. Kind of hard to evaluate, though the circuit you posted, we can say with certainty, will do nothing...
  12. BobK

    Ramping voltage to current converter?

    Yes, it is single supply. Dual supply op amps cannot have output a voltage near either rail. The only way you can get an output of zero is to have a positive and a negative supply. Single supply op amps can have an output near zero (but not exactly, it will typically be limited to a few 10s...
  13. BobK

    Ramping voltage to current converter?

    It is not rail to rail but it is single supply. It can go to near zero, but not all the way up to the supply voltage. That would be okay for your application. Bob
  14. BobK

    right amplifier size for speakers

    And power ratings of speakers are often grossly exaggerated. If you 160W speakers weigh less than about 10 lbs each (the raw speaker, not the enclosure), I would be suspicious of the rating. Bob
  15. BobK

    50w rms into 8 ohm load amplifier circuit using single dc power supply

    Using an amplifier with lower power does not affect the quality of the sound as long as you don't overdrive it. It only effects the loudness. Because hearing is logarithmic, going from 20W to 50W will give you a perceived change in volume of less than double. Bob
  16. BobK

    Ramping voltage to current converter?

    For the voltage range converter, it would be easier to use a difference amplifier with the inverting input connected to a 0.4V reference. Then, using a rail-to-rail op amp, you would not need a negative supply. The rest of the circuit is that same, a voltage controlled current source that puts...
  17. BobK

    New idea for oscillator

    You could use a long wire to delay a signal and feed it back to an input in an oscillator. Not sure that is what you are talking about though. Bob
  18. BobK

    Hi folks! I'm new here and don't understand JFETs

    @hevans1944, you might have been at Kubasaki at the same time as my older brother. He was there in 56 and 57 for 9th and 10th grades. He played on the basketball team. Meanwhile I went to Kindergarten in 57 at, I think I remember Naha or Kui (spelling?) One of those was where we lived and...
  19. BobK

    Accuracy Component Tester.

    You cannot have more accuracy than you have resolution. But the reverse is not true. In your 0.01 example, if it can only display the 1/100 digit, the true measurement might be anywhere from 0.0005 to 0.015 and it would display 0.01. So the precision is about 50% Bob
  20. BobK

    Just a quick check of my circuit

    I guess that is why you should ask for a review first! :) Bob
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