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  1. (*steve*)

    Challenge of Voltage/Digital standards differences between USA and Asia

    It sounds like your step down transformer is either an isolating transformer WITHOUT the earth connection being maintained, or possibly that you are using a plug somewhere that can be connected either way around and that you have an autotransformer which is connected so that neutral is not...
  2. (*steve*)

    Burleigh PZ-70

    Aha! Mine is actually in perfect working order! My fault was that I didn't wait long enough for the tube to warm up. What symptoms does yours have? Can you see the tube's filament glowing? Do you have the clear back cover in place? Do you have the various links in place on the rear...
  3. (*steve*)

    Getting into hot water

    Actually, the person was representing a company that is paid a relatively small sum to keep it working indefinitely. A real fix for them is not having to repair it again (and they are not in a position to refuse to fix it)
  4. (*steve*)

    help with schematic

    Just be especially careful. High voltage and high frequency can act in ways lower voltage and lower frequency don't. For example, you can easily and safely place your hand on top of a van de Graf generator whilst standing on a huge insulator and then power the thing up. You wouldn't try that...
  5. (*steve*)

    Automatic Re-setting target

    Google "useless box". I think we just found an application for it.
  6. (*steve*)

    Getting into hot water

    Did you note that the wire jumpers were a factory mod. They clearly didn't fix the problem. However I concur that the soldering was likely the primary fault in this case.
  7. (*steve*)

    MOSFET to replace a relay

    If the voltage is low, there are many options. Some as low as single digit milliohms. For such low currents I cant see the resistance being a huge issue. Are you really concerned with nanovolt differences in voltage?
  8. (*steve*)

    Burleigh PZ-70

    Does anyone have any information on these? I have a sick one.
  9. (*steve*)

    help with schematic

    It's a very poorly drawn schematic. There is either a single power supply or sparks! However if the 16 to 30V is connected ONLY to the upper end of the transformer and NOT to the rest of the 555 circuit it is conceivable that you could use two separate power supplies. In fact, given the...
  10. (*steve*)

    Any ideas - Rotary momentary switch?

    How about a rotary encoder?
  11. (*steve*)

    Help amplifying a tiny current

    No, you need a transistor just like in your first post.
  12. (*steve*)

    It's 1890!

    That's it Hop! Take back some MRSA!
  13. (*steve*)

    How can i add a trigger to this circuit to make it not electrocute the user?

    You can get way more than 2mA. The current specified in the datasheet is for the output voltage to be within the valid prior voltage range
  14. (*steve*)

    Need help repair Sunshine ATX psu

    You don't mention what the 60w bulb does. Does it light up at all?
  15. (*steve*)

    Need help repair Sunshine ATX psu

    Is that 5V from the standby 5V lines? If so, you need to enable the power supply. If you're already doing that then check the enable circuitry.
  16. (*steve*)

    Op-amp Current Source Analysis

    Unless your main opamp can supply in excess of 500mA you have a problem. Use a transistor or mosfet to give you additional current drive. You may be better off using a P channel mosfet and swap the inverting/non-inverting inputs. If using a mosfet, and you can use the 0v rail as the power...
  17. (*steve*)

    Schematic capture software recommendation

    Kicad is Great. It does ask this things. Once you've learned how to master it and become competent, there will be a short time left before the heat death of the universe. My experience was that kicad could do everything I needed and more, but it required a dedication I thought I was prepared...
  18. (*steve*)

    Help amplifying a tiny current

    Even without the additional pull-up resistor, the original circuit should work with the SSR. This (using an SSR) will give much longer battery life as well as having high voltage connections that are well away from the more voltage (which is not the case with most relays). My vote on design...
  19. (*steve*)

    90v/100a DC Power Supply

    Yeah, but you need to be able to supply the startup current.
  20. (*steve*)

    90v/100a DC Power Supply

    Hey, weren't you going to put that in an 8oz. Mailer bag and send it to me?
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