Archive for the ‘Electronic Components’ Category:

2019-04-08 Output Transformers Construction

from FB group Regenerative Receiver… Apr 8 庄议翔 The power transformers have the laminations interleaved. The first lamination has an E then I, the next one has I then E. So the transformer core does not have any air gaps, because it does not have any DC flowing through the windings. The transformers for single

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2019-03-31

from FB group Vintage transistor Radios April 3 Are all ‘polyvaricon’ tuning capacitors the same? They’re all about the same size. Charles Vesser Japan Industry Standard… The few that I have examined were 140 pF antenna and about 70 pF oscillator. In parallel give 210 pF. They’re probably made to match up with the loopstick

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2019-03-17

From FB group Building Transistor Radios 2019-03-19 John Ferguson Yeah, I used to use the Sylvania ECG and the NTE catalogs to cross-reference transistors. But then I got some better product manuals from the makers, especially Motorola and National Semi. And I got hold of the professional industry documents. ECG and NTE give a ‘one

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2019-03-15 The Tape Recorder 6V6 Making Crackling Noise

from FB group Building Transistor Radios Tuck Choy I was a reel to reel tape recorder fanatic when I was a kid, and had a recorder with a 6V6 output to the spkr. The first thing I did was modify the recorder to add an external spkr. One time I plugged in a clip leads

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2019-03-07 Make a 4 Millihenry RF Choke

From FB group Building Transistor Radios Mar 7 I got some of these toroid cores a few months ago, and I got around to experimenting with them. I wound one with 21 inches (51 cm) of 30 AWG (.25 mm diameter) enameled wire. This covered the core with a single layer of wire. I measured

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2019-03-06 Ferrite Toroid Cores 61 Mix

from FB group Building Transistor Radios 2019 Mar 5 I bought a bunch of ferrite toroid cores: Fair-Rite 5961001101 have 61 ferrite material and they’re about $.50 from Arrow.com. They’re 1/2 inch (12.7mm) OD and 1/4 inch (6.35mm) high. The edges are rounded so they don’t scrape off the insulation of the fine wires. The

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2019-02-26 BF199 Half Price Offer Accepted

I made an offer for a lot of BF199 transistors on eBay, and got it. They wanted $9.90 for 200, so I offered $5.00 and they accepted my offer. That works out to 2.5 cents per transistor, not including shipping. There was only a single photo and the transistor in the photo was labeled PH

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2019-02-20 Old 2N708 Transistors

Feb 20 I got 21 ‘packages’ of 2N708 transistors for $.99 a package from Goldmine-elec.com. In the box were 42 plastic zip bags, each having 5 2N708 transistors, so apparently one ‘package is two bags. Each transistor is marked with the Motorola logo and 2N708 and on the top KOREA is stamped into the metal.

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2019-02-16 The Old Time Rejected Components Cartel

Left link to this on FB. I saw the Electronic Goldmine email ‘flyer’ ad for 2N708 transistors on sale so I had to order a bunch of those to experiment with. But their ad said nothing about them being NOS (new old stock). I’ve bought some junk from them before that were rejects or floor

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2019-02-05 Floating Detector Diodes Are Not A Good Design.

from FB group Building Transistor Radios 2019-02-05 Graeme Heal Aaron Cake has a lot of good circuits and projects. But this one uses the ‘floating detector diode’ with no DC return path, so the circuit will only work if the diode’s leakage current provides the discharge. That means the diode must be germanium, not silicon,

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