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  1. BobK

    Boost AC circuit

    Or, based on your original idea. Use a relay to switch power to on an ordinary inverter. No need for a grid tie one. Also, you could add a separate power cable to avoid the voltage drop, assuming most of it comes from the 1500 ft cable. Bob
  2. BobK

    Boost AC circuit

    Would there be any problem with just turning off the air pump while the well pump was running? This would be far simpler. Bob
  3. BobK

    Astable / scope problem

    Which is basically what I asked you in my first post. When you are asking for free advice, complaining about how it is expressed seems a bit petty to me. Bob
  4. BobK

    Noob question regarding 555-DPDT relay-Motor

    That could work if accuracy of the timing is not that important. Bob
  5. BobK

    Optoisolator Circuit

    Bipolar transistors behave better when doped with Lithium. Bob
  6. BobK

    Solar Car, Voltage determines Velocity

    If you want to control the speed of the two wheels to determine the direction of the car, you need a motor speed controller (PWM) between the battery and the motor for each wheel. Then you need something that sets the duty cycle of the controller. Basically, you need a microcontroller or...
  7. BobK

    NP's of a Schematic

    The position of the line only indicates which lead is the cathode. It has nothing to do with the characteristics of the diode. Bob
  8. BobK

    Astable / scope problem

    You cannot do that. The grounds on the two probes are connected together, so you are altering the circuit when you connect the two grounds to different spots in the circuit. Bob
  9. BobK

    Cost-effective Production-Prototype Manufacturing

    Whoops, I meant 50x50mm or 2x2 inch, not 200mm. Bob
  10. BobK

    Mobile charger to charge LiIon batteries, Usng Voltage Divider to drop voltage

    This is best done in a fireproof bag just in case the LM317 fails shorted. Bob
  11. BobK

    Astable / scope problem

    Are you connecting the ground leads of the two probes to different places? If so, you are creating a short between them. Bob
  12. BobK

    Mobile charger to charge LiIon batteries, Usng Voltage Divider to drop voltage

    You cannot do it either a constant current or a constant voltage. A LiIon charger must start with a constant current, then change over to constant voltage, watching the current and stopping when the current becomes small enough. As A.G. said, you need a chip to do this right. Bob
  13. BobK

    Cost-effective Production-Prototype Manufacturing

    Your post does not explain exactly what they were quoting for. If it is just making the PCB from your Gerber files, that is way out of the league. You didn't state the size, but you can get 10 copies of a 200mm x 200mm board for $10 from many different Chinese manufacturers. If, on the other...
  14. BobK

    Step down transformers

    The question is why the primary is rated at 240V 10A, which is 2400VA. IMH0 this is simply a mistake. Bob
  15. BobK

    Step down transformers

    The answer was given in the first post. Those specifications are wrong. Bob
  16. BobK

    Emergency lamp

    The fuse in your multimeter is blown. There are two of them, one for the 10A and one for the mA range. The mA one is blown. Bob
  17. BobK

    Multitester PM8232 - Where is the fuse?

    Glad to be of help! Bob
  18. BobK

    Multitester PM8232 - Where is the fuse?

    Just a guess, but, take off the rubber boot and you should be able to open the back with a couple of screws. Bob
  19. BobK

    LM358 one opamp fails Please sugest what to do..

    You show two unconnected inputs. The difference may be 75 mV as you say, ut what about the voltage with respect to ground? Is there even a common ground between your circuit and the source of the inputs? Bob
  20. BobK

    How Does One "Provide" A Different Level Of Current?

    Reminds me of the very old SNL skit "The Pepsi Syndrome", where the reactor is about to melt down and the operators are arguing the meaning of the line in the instruction manual that says, "You can't have too much water in the reactor." Bob
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