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  1. (*steve*)

    How to modify 12-24v car phone charger?

    Oh, 9V at 600mA is 5.4W, while 5V 1A is 5W -- you're actually asking for more power, not less.
  2. (*steve*)

    How to modify 12-24v car phone charger?

    On that, possibly not. Some have a pair of resistors used to set the voltage and you can vary one of these to change the voltage. This does not appear to be amenable to such a simple modification. The AD85063D seems to have datasheets in Chinese only and also appears to have a fixed 5V...
  3. (*steve*)

    Common Base

    Take the transistor out and place a line between where the emitter and collector were connected.
  4. (*steve*)

    Why DC motor draws more current with friction?

    No, you wouldn't. All you can see is the reduced demand for current which implies either an increase in resistance or some other force acting against the current. It's not resistance :-) If you disconnected the source of voltage, you would see the voltage being generated by the motor...
  5. (*steve*)

    Switch activated by Amps

    Even better, the fan would only come on if the temperature exceeds some temperature. What voltage does the fan run at? If it's 12V then I'd go looking for devices designed for use in PCs. Here is a simple option that would run the fan slower when cooler. This can be simply redesigned for...
  6. (*steve*)

    Common Base

    if you short out the transistor, what is the combined voltage across Vb and Vl? for the purposes of calculation you might also want to include Ib in your final calculation, but this may be both unknown and small
  7. (*steve*)

    Why DC motor draws more current with friction?

    recall that if you spin the motor by hand a voltage is generated also recall that the motor has a low resistance and should draw a high current due to this. and have you wondered why a motor doesn't turn faster and faster and faster without limit? or perhaps why a motor runs faster at higher...
  8. (*steve*)

    Question about current

    Do you have a link to the stepper motor, power supply, and controller board?
  9. (*steve*)

    Unknown voltage of a Op amp

    one should also point out the voltage drop across R1 for a perfect op-amp would be...?
  10. (*steve*)

    Question about current

    Hmmm, newbie mistake. You should never try to measure the current from a voltage source. By calculation, the maximum DC current you should draw (presuming you have a bridge rectifier/cap/linear regulator is about 8.34/sqrt(2) or about 5.9A. Trying to measure current without a load (i.e...
  11. (*steve*)

    Looking for cheap ammeter that measure the smallest amp

    Is it possible that it only works on the 10A range? If that is what is happening then you have blown the fuse in your multimeter.
  12. (*steve*)

    Determine the unknown voltage in an ideal Op-Amp circuit

    The point of this area is to help people with their homework. We have no desire to cater for those who get an assignment, have no idea what it means (due, perhaps, to not doing any study) and come here for the answer. The initial question looked good. It was an ask for a push in the right...
  13. (*steve*)

    Salvaging an HDTV tuner for use as an external

    nowhere in a digital TV is the digital signal converted to a traditional analog signal. This means you need to find a way of converting the decoded digital image to an analog rasterised image.
  14. (*steve*)

    Looking for cheap ammeter that measure the smallest amp

    just to confirm... @dante_clericuzzio are you after a regular multimeter with probes or a clamp style AC current meter?
  15. (*steve*)

    Playing with valves

    I may not be making valves, but I have to make valve sockets! And another view. A wooden 12 pin socket. When I'm running tests I use a special set of probes I've made.
  16. (*steve*)

    Determine the unknown voltage in an ideal Op-Amp circuit

    you appear to confuse "help" with "doing"
  17. (*steve*)

    Building a current source

    you definitely don't need a PID controller for a constant current source. If you tried to use one the response time would be abysmal. I think you should look for another application where such a controller would be an advantage.
  18. (*steve*)

    Building a current source

    why do you need a PID controller to maintain a constant current? Can you describe what you want to do and why (not how)?
  19. (*steve*)

    Wanted: Free

    post some photos. I'm sure we can give you some answers. this thread is probably better placed in another area of you're after information. We probably don't need the bribe :)
  20. (*steve*)

    Determine the unknown voltage in an ideal Op-Amp circuit

    are you trying to get banned @Herschel Peeler? FFS, we want the OP to come up with this on his own, not be spoon fed the answer. And the ratio of resistor values is critical, which is why they're given. sheesh
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