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  1. (*steve*)

    power jack for hp3800A

    I saw four of them on eBay. But they're pretty expensive. Unless I was wanting to restore something to as-new condition as a collector I'd investigate replacement as Harald suggests.
  2. (*steve*)

    LCD TV repair. Momentary backlight

    The first thing is that if something is rattling around inside, don't apply power. If it's a piece of plastic it probably won't do any harm, but if it's metal it can potentially leave a new fault wherever it lands while power is applied.
  3. (*steve*)

    power jack for hp3800A

    I bet it's the one on this page https://www.cs.ubc.ca/~hilpert/e/powerConn/index.html Second from the top.
  4. (*steve*)

    ID glass cartridge fuses ???

    You can pass an ever increasing current through them until they blow... Are the markings unreadable, or is it that you can't read them?
  5. (*steve*)

    relay sticking

    I fear the adhesive properties in the longer term. I have a garage door opener which had sticking relays. The easiest solution was to replace the relays. In my case SSR was not an option (the relays were SPDT). I'm pretty sure that my sticking relay contacts were caused by the initial surge...
  6. (*steve*)

    Component ID

    Oh, and don't remove those capacitors from the board. Or if you do, make sure you either label them or have the equipment on hand to measure them. They are not marked (this is normal) and there is no way to determine what value they were if you lose them.
  7. (*steve*)

    Component ID

    Here are the options I have listed for BR (in small 3 pin devices): Narrowing it down to SOT-23 doesn't really help :-( I would be tracing the circuit to determine what the likely options are. It looks like these components drive Q3, so I'd check Q3 to make sure it's intact too. Given that...
  8. (*steve*)

    Wifi extender parabolic dish and other methods

    Several miles. Easy peasy. Good antennas and line of sight is all you need. With high gain antennae, your main concerns become the curvature of the Earth and legal limits on EIRP.
  9. (*steve*)

    Business Cards

    Another option is to print them on card of a suitable sure and to use a laser cutter to cut them. A sufficiently high power laser cutter will cut the paper with minimal discoloration. Where to find a laser cutter? Do you have a local hackerspace (aka makerspace). They may have one.
  10. (*steve*)

    How to limit solar current input for testing

    SNAP
  11. (*steve*)

    How to limit solar current input for testing

    No, the output is limited to 250mA. The input will be something like 50mA. You limit the input current by ensuring you don't apply a load which requires more than 250mA. If it's a lead acid battery system, the voltage will be insufficient to charge it.
  12. (*steve*)

    frequencies

    It's electromagnetic energy. The speed that it travels if the speed of light (since it is a form of light, or more correctly, visible light is a form of electromagnetic energy) The frequency is the rate at which the magnetic field and the electric field go through a cycle of changes in...
  13. (*steve*)

    Capacitor Protection Boards- How do they work?

    Did you check out the link I provided? That should give you the general idea. There is at least one track on the other side of that board that we can't see, so we have to guess where it connects to.. Read the datasheets of the components we've identified (Q1 is unknown, but afaik all sot23...
  14. (*steve*)

    Anyone ever build a DC to AC inverter ? Needs to run on 32v DC

    Changing to LED illumination and running that from your 32V source will be way more efficient too.
  15. (*steve*)

    Capacitor Protection Boards- How do they work?

    Heh, that too. edit: and V3 on Q1 is likely to be an NPN transistor, and do I see "431" on U1?
  16. (*steve*)

    Capacitor Protection Boards- How do they work?

    With a bit of experience you'll realize that a double diode is going to be a very unlikely find in a circuit like this.
  17. (*steve*)

    The collapse of a magnetic field

    Yep, that looks to be what I was suggesting ;-)
  18. (*steve*)

    The collapse of a magnetic field

    No, the current flows the same way through the inductor, it doesn't reverse. Edit: or maybe yes. Whatever... the current doesn't reverse.
  19. (*steve*)

    The collapse of a magnetic field

    The way you have your circuit drawn the capacitor will charge from the battery and when the switch is opened the voltage spike will destroy the diode and discharge the capacitor (and maybe ring for a while). Keep switch 2 closed and change the polarity of your battery and it will work the way...
  20. (*steve*)

    Capacitor Protection Boards- How do they work?

    Designations aside, the circuit seems very similar to the one I discussed here. The obvious differences are: Yours uses a BJT as the pass element Yours has load resistors to both limit current and to help dissipate heat. Mine has a pulldown resistor for the gate of the mosfet that is not...
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