From FB post about Arduino driving a ‘HC595 chip. You don’t need an oscilloscope to see digital signals. If you slow down the speed, you can see what’s happening by looking at LEDs. Everything is digital, just on or off. Plug two red LEDs, transistors, and current limiting resistors for LEDs (330 ohms), and for
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I received the transistor tester that I ordered a week or so ago. I ordered this one preassembled (the price was only a few dollars more) and with the plastic case, which I have to assemble. I ordered it from a seller on eBay for $20. This is different than the component tester I bought
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I was asking about very old capacitors and their shelf life on FB vintage test equipment group. The guys tell how good the old capacitor testers are because they have the “magic eye” to check for leakage. I was thinking that it would be easy to test any capacitor for leakage. All that’s needed is
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From a 2017-06-10 comment regarding a Weston capacitance meter on FB group vintage test equipment Reminds me of the ” kicker” meters the phone techs used on the phone lines. There was a polarity switch that reversed the pair, and the tech could tell about the line from the kick the meter needle gave when
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I got these today in the mail. Notice the temporary wire I poked into the connector. I ordered some adapters but I haven’t received them yet. I bought a frequency counter with the rubber ducky antenna but it doesn’t have the sensitivity that this cheap one has. I got two of these for $28, free
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A detector or discriminator in an electronic device might need to be adjusted to a very few points on a scale of a hundred or more points. A digital indicator typically indicates only a fraction of that, possibly 16 points. This is why the analog meter is still useful: it can indicate a small change
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It’s been awhile since I blogged this, so I may be saying what I’ve already said before. But I get comments from others about how to make measurements of the LED brightness. A recent one is in the comments of an older blog. Many Joule Thief builders don’t have the minimum tools needed for some
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This is about electronics components, despite this off-topic intro. Last night I watched a Frontline episode on PBS about the drug resistant superbugs that are resistant to antibiotics. They talked about one of the genes that causes this drug resistance; it produces an enzyme called klebsiella pneumoniae carbapenemase or KPC. I searched for KPC online
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A few weeks ago I ordered this kit on a whim, not knowing what to expect, just something to assemble and get some soldering practice (this is what it looks like). There are several Chinese vendors that sell them. The info claimed it tested other components besides transistors. It shipped from China so it has
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A relative was more than a little bit concerned, and sent me this link. Dangerouse 32,000 mcR/h Radiation Reading by My New Geiger Counter from …: https://youtu.be/VuGL97jjI3k These are false readings. The Geiger counter is receiving electromagnetic interference from the light and falsely interpreting it as counts per minute. There is actually very little radiation
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