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  1. alfa88

    blowing up capacitors

    Ah finally my favorite subject. As suggested before use eye protection and preferably from a distance. The direction of the projectile/s can be unpredictable. The rating is also called WVDC(Working Voltage Direct Current). That refers to the maximum Voltage that the cap will take in either...
  2. alfa88

    Voltage Follower

    I'm finding it hard to believe this circuit isn't working. It's almost verbatim to what's on the datasheet. Without the transistors there is the full adjustment range (1 to~14V). With the transistors the range is 12 to ~14V. I left the capacitors out for ease of experimenting. UPDATE: My bad...
  3. alfa88

    New Power Supply

    It looks like I under estimated the transformer. I got a 4A transformer since I was building a 4A power supply but at a 4A load the Voltage drops miserably (from 15 to 10). I'm wondering now if I should over rate it by, say, 125%?
  4. alfa88

    What did I do?

    I hate to ask the obvious but have you checked the fuses?
  5. alfa88

    Looking for Clarification on Some Things

    Perhaps your wire confusion stems from wire gauge numbering. I speak of AWG(American Wire Gauge). Who thought this scheme up? The larger the number the smaller the wire. Ergo the larger the gauge # the more resistance. But then past #1 gauge they change it around and the scale goes to 1/0(1...
  6. alfa88

    IC socket orientation - I made a boo boo!

    You might want to use an Xacto knife to cut a corner off the pin 1 side to try and undo the boo-boo in lieu of unsoldering.
  7. alfa88

    What can a analog volt meter do that a digital one can't?

    I find resistance checks on diodes and transistors with digital meters inconclusive. Analog meters exel in that respect. IMHO
  8. alfa88

    New Power Supply

    I'm soooo confused. I want to have adjustable current limiting and I came across this scheme in a couple of different places. I don't see how this can possibly work. is this a hoax?
  9. alfa88

    Test Equipment Importance

    Right now I'm in the process of rebuilding my power supply. It wont be quite as lofty as Dave's suggestion but it will be close. I'm sure there'll be some back and forth on this forum as I get the design ironed out. Parts are on order so stay tuned. I use a Weller WTCPT soldering iron. It uses...
  10. alfa88

    Test Equipment Importance

    Probably better than my Harbor Freight Cheepo-meter
  11. alfa88

    New vs Old Electrolytic Capacitor Sizes

    I was marveling at the very thing the other day when I was harvesting parts from some wall warts. What was a large 'pill bottle' sized capacitor in the tube days is now smaller than my pinky.
  12. alfa88

    Test Equipment Importance

    Instructables has a TV O-scope tutorial. I wouldn't expect too much from it but it's something and cheap. Search on Fully Functional Television Oscilloscope
  13. alfa88

    Oh what to do with a Tetrode tube????

    Yikes! CRT plate voltages are pretty high. Take baby steps. You may not even need a kV. Look at some Audion schematics. An uber power amp might be too lofty an expectation and besides, once the tube/valve heats up maybe that's when it shorted out for the radio shop guy.
  14. alfa88

    Unknown zener

    An active test on the diode would confirm things but if you insist go with a 6.5@1Amp Zener then have a Voltmeter hooked up and be quick on the power switch. I sometimes get flack for my cowboy approach to electronics. No guts no glory I guess.
  15. alfa88

    Oh what to do with a Tetrode tube????

    That's a good question. At first thought I was going to say AC but if there's no cathode to boil off electrons from so then I say DC.
  16. alfa88

    Oh what to do with a Tetrode tube????

    I'd say he was referring to High Tension, a.k.a., High Voltage. If there were a short my guess is that it would be between the filament and the grid due to their relative proximity. I'd start out with 1Volt on the filament, gradually increasing to the level, until you get a pleasant orange glow...
  17. alfa88

    Oh what to do with a Tetrode tube????

    It looks like a triode to me too. I recently acquired an Audion tube/valve but yours makes mine look compact! You might want to join the diytube.com forum to maybe find someone that's seen them before.
  18. alfa88

    Unknown zener

    Keep in mind that the 6.5 Volt figure is only a wild guess. Bad Things could happen if it were wrong. Are you using a digital meter to measure diodes? I usually get conflicting results using DVMs when Ohming out diodes. This is where analog meters shine.
  19. alfa88

    Unknown zener

    No schematic but I could guess at the value. 6.5Volts. You would also need to know how much Amperage the diode will handle. No Idea. To positively pinpoint the voltage of the Zener (assuming it is good) you need a power supply, 1k resistor and Voltmeter. Clip leads would help.Connect as shown...
  20. alfa88

    Old Zener Diode

    Tada!:D
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