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  1. (*steve*)

    MFOS VCO fault

    Place some 100 ohm resistors in series with your +12V and -12V supply. They may affect the circuit somewhat, but they'll protect your power supply, and possibly most of the circuit. (while you're testing)
  2. (*steve*)

    Current Operated Relay

    Because you are applying AC to a LED. When forward biased, the forward current may be enough to damage the LED, but let's ignore that. When reverse voltage is applied, 170V or so will appear across the LED with a breakdown voltage of around 7V. **POOF**
  3. (*steve*)

    ETI magazine Feb 1979 - power supply (ETI-142)

    Ok, starting with my 100 ohm resistor. 100Ω PSU goes from 162mV up to 33.2V. about 0.5mV ripple 10Ω at 22V 1.27mV ripple 1Ω PSU goes from 2.7mV. At 14V output there is 0.45V of 100Hz ripple and I'm drawing 2A from the mains. And yes, my dummy load actually got warm for the first time :-)...
  4. (*steve*)

    ETI magazine Feb 1979 - power supply (ETI-142)

    Ok, I've finally decided to spend a few moments doing some basic checks. Both windings of the transformer are ok. I get AC at the secondary I get DC after the rectifier With 100V input voltage (240V mains) there apparently no load on the DC rail. After applying 240V to the unit I noticed...
  5. (*steve*)

    MFOS VCO fault

    When you say the pots failed, were there any that had to be replaced, or did they just not perform the adjustment they should have? Where was the pulse adjust width control when U6 failed? Was it at one end? Is it possible that R39 was miswired?
  6. (*steve*)

    MFOS VCO fault

    Is it possible you connected the power around the wrong way at any time?
  7. (*steve*)

    Current Operated Relay

    I imagine the progress is going to be that you report a blown up LED.
  8. (*steve*)

    Convert AND/OR logic circuit to NANDD-NAND logic circuit

    Did you forget NOR? And your rules will change the function of the circuit.
  9. (*steve*)

    Can i plug a 115v power bar to 110v - 240v extension?

    No, travel adapters don't convert voltage. The power bar (multi outlet power board?) Should be fine. If it has a MOV in it to protect things from excess voltage, it will die immediately.
  10. (*steve*)

    how to make Regulated power supply of 0 - 48V 5Amp using 24-0-24 V 5Amp center tapped transformer?

    The transformer is not capable of 48VDC at 5A unless you use a switchmode regulator (and even then, you'll be asking for more than 100% from it).
  11. (*steve*)

    MFOS VCO fault

    Ok, if it was working and calibrated, then assume the components are correct. Something must have happened between them and now (unless you power supply or the design is badly at fault). Which ic went up in smoke?
  12. (*steve*)

    Programming starting point

    The first thing you need to know is what the program needs to do. The next thing is what the inputs and outputs are. One you've got that, if you don't have a good idea in your head about how to do it, the next step is research. After that, take a look at what is already written. Maybe you...
  13. (*steve*)

    MFOS VCO fault

    Did this fault develop, or was the unit never working?
  14. (*steve*)

    What does your workshop / workbench look like?

    I'm beginning to think I can use one to carve out an entry into my workshop.
  15. (*steve*)

    Should I apply pressure occasionally to a burger when I'm cooking it?

    Did I say implanted? I meant "pressed" :-D
  16. (*steve*)

    Appropriate driver for an IGBT 600 V

    Essentially you are probably looking for a gate driver. There are many differences between MOSFETs and IGBT's, but both have similar gate drive requirements. Generally speaking, you want them to switch fast, and for that you want a low impedance driver (i.e. one able to supply significant...
  17. (*steve*)

    Should I apply pressure occasionally to a burger when I'm cooking it?

    Do you mean that the presence of my tongue being firmly implanted in one cheek was not-obvious?
  18. (*steve*)

    What is your troubleshooting sequence?

    In my explanation I mentioned "obvious faults". My first step is a thorough visual (and often olfactory) examination. How thorough depends on the nature of the fault and the difficulty in disassembling the unit, but examining what you can first with an unaided eyeball, and then under...
  19. (*steve*)

    Reading value from Solar Panel Cell, current peak concern

    You may find that you get prettier bell shaped graphs of you measure max power from the solar panel. Unfortunately that is significantly more difficult. I think it's best you try out the simple method first and see what results you get. If you find they're a bit pointy, we can talk about what...
  20. (*steve*)

    Reading value from Solar Panel Cell, current peak concern

    Yep, that's kinda what you should expect. Put a 50Ω 1W resistor across the solar panel and you should get something better.
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