I need a source of signals on various frequencies to test how well my bandpass filters are aligned. I built a Vackar Oscillator with tuning over a few CB channels, mainly 27.095 to 27.255 MHz. These are radio control frequencies. Like a Colpitts oscillator, the Vackar’s resonant circuit has two capacitors in series with the
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I’m trying to make a simple wireless alarm link. The transmitter will be in an unheated garage, so the only way to easily get it to stay within the -+ 10kHz channel will be to use a XO (crystal oscillator). But for the receiver, I figured the best way to go would be to
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I think I’m set for life when I need SMT transistors – I bought hundreds of them from Newark Element14. They are having a discount sale; some of these transistors are discounted to less than 2 cents apiece whether you buy 1 or a thousand. Some are as low as a penny – $0.011. The discounted
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I had problems with the blog and I had to reinstall the app. All of the local copies got deleted from Jan 21 up until today. I haven’t been able to do any blogging or moderate comments since Jan 21.
Someone said that you’re not a tech until you blow up a chip so violently that it imbeds itself into the ceiling. Well, this transistor seems to have exploded violently. It was inside a CFL bulb and when it went off, it probably wasn’t even heard. It handled over a hundred volts, and it was
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I’ve been building another FM regenerative receiver. This one is supposed to use a BF244 JFET. But they were declared obsolete years ago, and aren’t available in quantities at a reasonable price. So I ordered some 2N3819 JFETs from Mouser and got them a few days ago. The 2N3819 is also a VHF JFET, so
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Here’s a shot of one of my very bright work lights. It’s a 10 watt multi chip LED mounted on a heat sink, which gets a bit warm. I mounted the heat sink on a piece of 6 AWG bare copper wire which lets me reposition the light a bit. It’s a daylight color temperature,
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I bought two of these ‘roll of wire’ on sale at goldmine-elec.com. They came with the wire ends on the same end of the reel, the start end was sticking out of a hole and standing straight out, and the end of the wire was held to the reel with tape, exactly half way around
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I blogged this subject recently, but I am now using a bigger lens. The 3 inch lens was having a difficult time heating the two leads. This time I used first a 4 inch lens, then a 8 by 10 inch fresnel lens made for reading a whole page. The 4 inch lens was not
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