Archive for the ‘Uncategorized’ Category:

2018-12-12 LM78xx Linear Regulator Disadvantages

from FB group Building Transistor Radios 2018-12-13 Joseph Rotello I agree with some of your claims. But I know far more about 3-terminal regulators than you think. First off, your claim that they are more efficient is unproveable. There are linear PSes that are more efficient. That was the reason LDO regulators were used. You

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2018-12-03 My Fluke 75 DMM

from FB group Building Transistor Radios Joe Lima That’s good to hear. More than a year after I bought my Fluke 75 DMM (and with light use at home) I turned the switch to off but it stayed on(!!) I had to unplug the battery. Luckily it was still under the 3 year warranty, so

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2018-12-02 How to Determine If Diodes Are Real Germanium

From comment left for Roger Kainka Labs video on YouTube Another 100% accurate method of determining if it’s germanium is how sensitive the device is to changes in temperature. The leakage current of germanium is much more sensitive to temperature changes than silicon. What angers me is that some circuits are designed with depending on

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2018-12-02 How to Determine If Diodes Are Real Germanium

From comment left for Roger Kainka Labs video on YouTube Another 100% accurate method of determining if it’s germanium is how sensitive the device is to changes in temperature. The leakage current of germanium is much more sensitive to temperature changes than silicon. What angers me is that some circuits are designed with depending on

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2018-11-07 The 2 Transistor Boy’s Radios

from FB group Building Transistor Radios 2018 Nov 7 I bought some 10 uF, 10 volt MLCC (multilayer ceramic capacitor) capacitors, which do not have the electrolyte so they can’t dry out. They are smaller, too. If they are used for replacements, then radios might last much longer. About the only thing left to go

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2018-11-03 Three 1 Millihenry Toroids

from FB group Building Transistor Radios 2018 Nov 6 Chokes using a Fair-Rite 5943000201 toroid core, 3/8″ or 9mm OD. From 1.1 to 1.6 millihenrys using #30 or #28 AWG enamel coated wire. There is still room to wind more wire on them.

2018-10-12 Finding Transistor Substitutes

From FB group Building Transistor Radios 2018-10-12 Michael P. Hamilton After I got a National transistor catalog decades ago, I started to understand the way they were making and packaging transistors. They had lists of discretes, BJTs, FETs, etc. At the beginning of the line was the part number, then the parameters, and then at

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2018-09-11 Vectronics Aircraft Radio Kit

I got the Vectronics VEC-131K aircraft band radio kit in the mail yesterday and warmed up the soldering iron to assemble it. It came at a decent price, so some of my complaints seem to be cost cutting measures. It comes with a decent assembly instruction manual, but some of the pages including the schematic

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2018-08-27

From FB group Building Transistor Radios 2018-08-27 Michael Kronsteiner I would say that germanium transistors could not handle “high” currents because the designers were unwilling to use anything more than the cheapest germanium transistors that could barely do the job. In the 1960s there was the Workman “99 Power” that was in the TO-3 diamond

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2018-08-16 Cancer Loves Fat Cells

Sci Am article https://www.scientificamerican.com/custom-media/cancers-hidden-helper-your-fat/?utm_medium=Display&utm_source=1865911&utm_term=226398931&utm_content=101129235&utm_campaign=20582999

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