Recent content by kpatz

  1. K

    How to test if I am grounded properly to work with electronics?

    If you’re experimenting with electronics you’ll probably want to get a bench power supply with a 3 prong plug. Many of these have a ground terminal on them, so you could ground yourself to that. That would be the easiest way. Laptop power supplies are often ungrounded or have plastic cases...
  2. K

    Estate sale finds (vintage test equipment)

    I just purchased a Calrad 116B variac on eBay. Should have it next week sometime.
  3. K

    Are There 3 Volt MultiMeters?

    An analog meter only needs the battery for the resistance/ohms setting. So if your concern is buying batteries and you don’t care about measuring resistance, you can get an analog meter. Also, in analog meters the battery lasts a very long time (watch for leakage though). My first multimeter...
  4. K

    Estate sale finds (vintage test equipment)

    I opened them up to take a peek. They are all in excellent condition inside, no dirt or mouse stuff or anything. They were well kept. The oscillator almost looks like it was never opened since it was built. The Sabtronics frequency counter (which is from 1979) appears to work, the only fault...
  5. K

    Estate sale finds (vintage test equipment)

    Hi folks. I haven’t been on these forums in a long time. Lots of life changes. But anyway… I hit up a local estate sale and came home with some vintage electronic testing equipment. I’m hoping to restore them to working order and either keep or sell them. B&K 801 Capacitor Analyst Jackson...
  6. K

    Replacement LED for Guitar Effects Pedal (Ibanez Tone-Lok CF7)

    You can also use the multimeter to see if any voltage is reaching the LED with the pedal turned on. That will save you from unsoldering the LED and buying a new one if it turns out the problem isn't the LED itself. If you do need to replace it, you can use any red LED, but finding one the same...
  7. K

    Photodiode falltime problem

    There's two ways to use a photodiode. One is photovoltaic mode, where it acts like a tiny solar panel, generating a voltage when light hits it. The diode will have a slower response when used in this manner. The other way is to reverse bias the diode, and detect current that flows when light...
  8. K

    power supply to 1,5v (clock) AND 3v (LED)?

    Is this an analog quartz movement clock (with hands) or a digital LCD display? Considering the clock uses such a minuscule amount of current, you could use a 5V USB power supply (phone charger or similar), a simple voltage divider to power the clock and a current limiting resistor for the LED...
  9. K

    Comedy Thread

    No Fish Hooks You're going in circles Man peeing in storm drain next to curb Warning, you'll be cut in half at the waist!
  10. K

    Signal Generator's actual and expected output differs - is it broken?

    When you switched from x10 to x1 did you do it in the scope settings or on the probe itself? The probe should have a x1/x10 switch on it. When set to x1 it passes the signal as-is. When set to x10 it attenuates the signal to 10% of its actual voltage, to allow measuring higher voltages than...
  11. K

    Signal Generator's actual and expected output differs - is it broken?

    Are you sure the scope is set to 5V/div? It's not clear looking at the image... I don't own that scope so I don't know what the indicators on the display mean and if they represent V/div. Some images I've seen of the same scope on the internet shows it can display Vpp for a waveform, maybe...
  12. K

    Arduino Resets -- Why?

    The capacitors seem to be correct. It wouldn't hurt to add a 0.1μF capacitor after the 10μF one on the 5V side. The SRD-05VDC-SL-C is the part number of the relay on the module. Do you have a part number or specification for the module? Where did you get it? When I say driver, I mean the...
  13. K

    Arduino Resets -- Why?

    As Bertus asked, what are the values of the capacitors? The reset is probably due to inductive noise from the horn, or a voltage sag depending on how much load the horn puts on the power supply. 7805 is a linear regulator, meaning whatever voltage (actually, power) that is dropped to bring the...
  14. K

    Clicking noise from cd player?

    I wonder if there's a bad capacitor or a floating ground that's picking up noise/EMI somewhere between the CD player DAC and the preamp circuitry. We've ruled out anything related to disc rotation since the cadence doesn't change. If you pause the CD does the noise also stop? What if you hold...
  15. K

    Clicking noise from cd player?

    Does the cadence of the noise vary with disc speed? CDs spin faster on the early tracks than the later ones. If you play the last track on a 60+ minute CD is the noise any different than on the 1st track?
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