Archive for the ‘Transistors’ Category:

2019-02-16 The Old Time 2N708 Transistor 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

(Read More…)

2018 Dec 8 Sinclair Book 22 Tested Circuits Using Micro Alloy Transistors

from FB group Building Transistor Radios 2018 Dec 8 Nick Bastian posted the schematic of a Sinclair Micromatic radio. I found the book by Clive Sinclair about the circuits using micro alloy transistors. Germanium transistors and especially micro alloy transistors are no longer made so it’s better to use silicon BJTs instead. Here is the

(Read More…)

2018-11-13 PSI Pacific Semiconductors Inc.

from FB group Building Transistor Radios 2018-11-16 The guy I worked for got us some Pacific Semiconductor power transistors for use in aircraft radios. That was before they were bought out. The logo on them was the Greek letter Psi. I think I might still have one in my old parts drawers. PSI was one

(Read More…)

2018-10-29 Early Transistor Radios And LW Band

from FB group Vintage Transistor Radios 2018-10-29 One may find that some early transistor radios, along with AM, had Long Wave band before they had SW or FM. We should keep in mind that earlier germanium junction transistors had a maximum frequency that was limited to 2 to 4 MHz. The radios could have a

(Read More…)

2018-08-24 2N3904 & 2N3906 for Output Transistors

From FB group Building Transistor Radios 2018-08-24 – The discussion was about the OTL complementary symmetry audio amplifier that Mr. Barnett has posted several times to the group, which uses a 2N3904 and 2N3906. Willie Barnett Let’s talk about current. Suppose your amp has a 9V supply. When the output transistor is turned fully on,

(Read More…)

2018-08-20 2N3904s From Mouser And Ebay

from FB group Building Transistor Radios 2018-08-22 Olek Kopyto I recently did some tests on 2N3904s I got from Mouser and from a Chinese eBay seller. The ones from Mouser had a current gain of right around 200, right in the middle of the 100 to 300 gain range according to the data sheet. The

(Read More…)

2018-07-26 Transistors, ECG, Motorola HEP Line, etc.

From FB group Building Transistor Radios Wayne Leake Yeah, the 2N3904 is E B C, THE ‘945 is E C B. Watch out the leads don’t touch and short. 😝 I have the Moto HEP catalogs, if you need to find out what it’s equivalent to. When National Semiconductor came out with their catalogs they

(Read More…)

2018-06-28 Bootstrapped For High Z Input

From FB group Building Transistor Radios For those who don’t want to or can’t use a JFET for high input impedance, you can use a regular transistor or two and bootstrapping to get a 10 Megohm high input impedance amplifier. This is from “Common Collector Amplifiers”, Electronics Now, Oct. 1993, found at americanradiohistory.com. For RFs,

(Read More…)

2018-06-20 2N176 PNP Ge Power Transistor Substitutes

From FB group Building Transistor Radios Nick Cook Have you found the reason for the failure of the 2N176? You could use the NTE equivalents NTE104 or NTE121. These may be expensive but they are the substitutes. But you have to make sure that the new one doesn’t burn out. You should be able to

(Read More…)

2018-06-19 2N3904 Transistors Betas

From a FB group Building Transistor Radios Markku Vuorensivu Tell me more! I’m all ears! I got a thousand 2N3904 BJTs from Mouser, and ten packs of 100 from eBay. I selected a dozen from each and measured their current gain using two methods: a cheap DMM, and a ‘transistor tester’ which has the ZIF

(Read More…)

© RustyBolt.Info/wordpress
CyberChimps