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  1. (*steve*)

    Looking for off the shelf wave generator with low internal impedance

    I would suggest a function generator followed by a high power amplifier. Why does it have to be off the shelf? Surely you won't be incorporating it into the finished product.
  2. (*steve*)

    Getting antenna to radiate

    I presume you connect the braid to the same location you connect the ground plane of your antenna.
  3. (*steve*)

    Need Experts Advice On Soldering Irons

    Good heat capacity, or alternately, the ability to get energy to the tip quickly. Next on my list is light weight, balance, comfort, and with a light and flexible cable that doesn't get in the way.
  4. (*steve*)

    Zener confusion

    Yep. Very well done :-)
  5. (*steve*)

    Zener confusion

    If it's still working you can test it by getting a couple of 9V batteries and a 10k resistor. Place them all in series (including your mystery diode) and measure the voltage across the diode. Turn the diode around and read it again. One way should measure under a volt, the other way will read...
  6. (*steve*)

    Where there's smoke...

    I think Dave was just offering to draw a picture of what he said in words to explain in pictures. In many respects schematics are just stylised pictures. They follow a set of conventions which allow information to be presented in a clear and unambiguous manner. Unfortunately that convention...
  7. (*steve*)

    Tektronix 577 curve tracer

    I have finally pulled out my Tektronix 577. It arrived with a few screws lose inside it, and the cover on one side has been removed and replaced incorrectly. Not a good sign. It turns out that the top and bottom section (the top section contains the CRT) were separated at the back and those...
  8. (*steve*)

    HP 54510A Power Supply Smelling

    The clicking may be as a result of gross overload of the power supply. If the voltage you gave earlier were with the PSU disconnected, check the rectifier diodes for the very low rails (12 and 15v) first. That would be CR24 on the diagram above It is also possible that C30 or C31 is...
  9. (*steve*)

    IGBT current limit

    The way to limit the current through the coil is to limit the time it is turned on. Once it hits the max current you turn it off
  10. (*steve*)

    Fixing an HP3455A multimeter

    I'm just really happy that the are people out there who are obviously willing to sell working test equipment at scrap prices. One piece of equipment was used by keithley as a sales tool. It has clearly been opened up many times, and was a bit bumped up, but has almost pristine controls...
  11. (*steve*)

    What the latch?

    If you have multiple inputs you want to reset with a single signal (using the method described above), then you'll need to isolate the rest signal with diodes. In addition you need to handle the case where the input is asserted at the same time as the reset. Judicious use of resistors can not...
  12. (*steve*)

    IRF5305S Power MOSFET, is switching voltages of 3V possible?

    Remember that the optocoupler will not pass all the voltage to the gate (it will drop some). I would think that anything less than 5V would be problematic. A MOSFET with a lower Vgs(th) might be able to be substituted.
  13. (*steve*)

    How can we Improve EP in 2017?

    Looks OK at work. I think I was using the same browser session as last night, so it was probably using an old version of some file.
  14. (*steve*)

    Where there's smoke...

    I think I suggested a 10ohm 1/2W resistor. You need one for each LED, but only in series with one lead (either one, it makes no difference). In that case you'll also have to remove one of the wires going around the LEDs (sorry). I'd still design it so it is capable of running at full power...
  15. (*steve*)

    Where there's smoke...

    I'm not sure the computer power supplies like that. Generally speaking they shut down if anything is badly wrong so you might be OK doing this. Again, no guarantee, but it certainly looks a lot better. I'd be pretty confident. I'll try to answer the rest later...
  16. (*steve*)

    How can we Improve EP in 2017?

    Have you done something accidental? The "Perform action with selected posts" banner appears even without any posts selected. I'm sure it didn't before... And I'm being asked "are you sure you want to like this post?" And the font in the editor seems smaller.
  17. (*steve*)

    IRF5305S Power MOSFET, is switching voltages of 3V possible?

    The important factor is where the voltage which is supplied to the gate of the MOSFET comes from. In most optocoupled circuits, this would come from the load side.
  18. (*steve*)

    IRF5305S Power MOSFET, is switching voltages of 3V possible?

    The Vgs(th) can be as high as 4V, and the device is specced for a minimum Vgs of 4.5V, so it would fall somewhere between "won't work" and "unreliable".
  19. (*steve*)

    Fixing an HP3455A multimeter

    Some of you may be aware of my huge stash of test equipment bought for a song and transported half way around the world at great expense... Well, among that stash is a couple of HP3455A multimeters. Because I had 2 of them I decided to take one down to my local hackerspace to equip them with a...
  20. (*steve*)

    Howdy all.

    Hi Mr X, welcome to electronics point and thanks for the entertaining introduction.
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