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  1. (*steve*)

    Led pinspot 2

    If open it up and start by looking for bad capacitors.
  2. (*steve*)

    How To Find Internal Short

    There are several possibilities. A simple one is that you (or someone else) connected the power backwards and an internal protection diode has failed short circuit. However it could be a whole suite of things. You need to open the device up and look for something that is obviously damaged...
  3. (*steve*)

    Reading value from Solar Panel Cell, current peak concern

    Solar panels may be more efficient in colder weather, but there's less sunlight available. An edge effect of clouds magnifying sunlight might be an hypothesis, that attempts to explain observed behaviour, but it's not correct AFAIK. You can achieve higher power output from a solar panel by...
  4. (*steve*)

    Identifying equivalent for surface mount diode from photo

    The fact that nobody has contradicted Dave is probably a good indication.
  5. (*steve*)

    Reading value from Solar Panel Cell, current peak concern

    Solar panels are less efficient when hot. What can happen is that the panels can cool when under cloud, then when the clouds go away the panels generate more power than expected until they heat up.
  6. (*steve*)

    Reading value from Solar Panel Cell, current peak concern

    Try what you have drawn in your latest post. Your confusion may be eased somewhere by understanding that a simple load has a constant resistance. The higher the resistance, the lower the load. The lower the resistance, the higher the load. Using a LED as a load gives you a very weird load...
  7. (*steve*)

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

    Yesterday I made a quick and dirty feedback circuit using an optocoupler, a zener and a few resistors. It made the per supply oscillate, so that's not a good thing. I also trimmed up the voltmeter so it reads a little more accurately. However I discovered that the ripple detection (for the...
  8. (*steve*)

    Please Help reusing speakers

    The connectors on the back of your TV are mostly RCA connectors. Three of the RCA sockets have RCA plugs in them. These connectors are normally used for low power signals, but I have seen them used for speaker connections on cheap equipment. In any case these all look like inputs to your TV...
  9. (*steve*)

    DC booster converter strange behaviour

    Is your load connected to the power source in any way? E.g. is it a light on a vehicle? Or is it completely separate, like 2 wires leading to a globe that's sitting on a wooden bench?
  10. (*steve*)

    DC booster converter strange behaviour

    Does this happen even when there is no load connected?
  11. (*steve*)

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

    I just checked the control voltage. With respect to the +40V rail it seems to produce a nice even voltage which rises as power demand from the power supply increases. With respect to other rails it has the same 100Hz artifacts. The funny thing is, that because the +40V rail has ripple, I'd...
  12. (*steve*)

    DC booster converter strange behaviour

    What are the input and output voltages when the bad stuff starts to happen?
  13. (*steve*)

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

    I couldn't wait... Here's the voltage between the centre tap of the transformer (referred to as +20V) and each of the supply rails These traces are AC coupled, and without thinking I inverted the second channel to make it look right. I shouldn't have needed to do that. There is an LC filter...
  14. (*steve*)

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

    Things to look at tomorrow: Ripple on unregulated DC rails WRT centre tap (50Hz or 100Hz?) -12V rail 20kHz sawtooth Error signal Ripple voltage at pin 2 of IC3 Setting of overload Have I overlooked something obvious?
  15. (*steve*)

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

    OK, there's something wrong with the switching pre-regulator. It's not putting out a voltage that is tracking the output voltage well. It seems to track something else instead... I have displayed here the voltage across the main regulator. There is supposed to be about 7V across here. I've...
  16. (*steve*)

    MFOS VCO fault

    Possibly not. Start with your current limit set to some nice small amount like 20mA and go from there.
  17. (*steve*)

    Current Operated Relay

    Fair enough. I didn't see them in his schematics.
  18. (*steve*)

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

    OK, so here's the results very quickly obtained from my analog scope. Firstly, 14V 14A output: Next 6V 6A output (and with the trace brightness turned down): And the same with a better vertical and horizontal setting This is 100Hz ripple, and I guess, if I take a look, it's the...
  19. (*steve*)

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

    I have a 110V power board that I use on 240V. The MOV died. Shrug. Sorry, I may have implied the power board would blow up. It's just the MOV. No huge concern, they normally die in a benign manner.
  20. (*steve*)

    Reading value from Solar Panel Cell, current peak concern

    Yes, 4 x 1/4W resistors will allow you to dissipate 1W. You DEFINITELY don't want a LED in there. If you have 6 or 7 330 ohm resistors, place them in parallel. You'll get a resistance close enough to 50 ohms for this purpose and it will be able to handle the power.
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