Germanium transistor tester vero. I have measurements for over 600 germanium transistors in my records, and 461 would be the second highest hFE measurement. Read the voltage and calculate the leakage. I made a slight change to put the switch on the board with leads for the DMM. G. 2N67 Western Electric Point Contact 2. The included germanium computer transistors are: 1. Once the pedal hacker community had the geofex gain/leakage tester, they went wild with specifying gains and leakages on new nuggets of germanium they found. 472 volts to display. Jan 18, 2021 · Small Bear germanium transistor test method Guitar Related Ramblings - Vero, P2P, Vintage Effects and Amps Guitar Related Ramblings - Vero, P2P, Vintage Effects Feb 23, 2022 · Test leaky 2N388 TO-5 NPN germanium transistor with known pinouts. htmUSING RG KEENS WONDERFUL GERMAN It probably takes an hour to test 50 transistors now that I have the tester build as a physical device. To do the test, stick the transistor in the socket, and read the DC voltage across the 2. it seems that the usable ones must have moderate leakage with hfe's around 50 to 150. 14 I say “we have here the Silicon transistor” but of course I mean: “The Germanium transistor” (!), also when explaining that This tool was built to more easily determine germanium transistor beta values for Fuzz Face circuits. 469k). You can buy our transistors in They should be germanium if you want to get the classic 60's/70's "soft" distortion. I sometimes start building on vero, then solder wires on temporarily to test different component values on the breadboard. com/2012/08/germanium-transistor-tester. Jan 21, 2024 · The test distinctly lacked scientific conditions - for starters I wasn't even wearing a white coat at the time, but the results seem to match the theory. Oct 1, 2012 · http://www. It's based on this article by R. 472k as possible (I got to 2. This is normal for a germanium transistor but if you have this with a silicon transistor, it is a defective silicon transistor or a "pre-biased" silicon transistor. G. Apr 27, 2021 · See “Figure 12: LTSpice simulation of oscilloscope / arbitrary waveform generator NPN transistor hFE test circuit” above for details. htmlhttp://www. Donc, il ne peut pas utiliser 4 transistors PNP AD152 ! Sur RadioMuseum. devices or 1000 pads. Jul 31, 2015 · Following on from the Transistor / Component Tester review and teardown video, I briefly introduce germanium transistors and see if they can also be tested w Jun 28, 2019 · Germanium Transistor Tester Collection of vero (stripboard) & tagboard layouts for 100s of popular guitar effects, with over 1000 verified designs. Keen's Geofex describes a method for calculating the hFE of a germanium transistor. Further research suggests this may be due to the tester getting thrown by voltage leakage, which Ge transistors are known for. I got the layout here. Apr 10, 2013 · Germanium transistor tester questions. The resistor will convert any leakage current from the transistor into a voltage that you can then read on your meter. A 2472 ohm resistor is 2. Probe base (positive lead) to the emitter (negative lead) using DMM’s diode mode. 472 collector resistor. So not impossibly high, but improbable enough to suggest that the transistor tester may not have accounted for leakage. geofex. I use a spreadsheet set up with the calculations ready to go for testing; there's also an online calculator here . For germanium transistors, leakage current mainly depends on temperature and doubles for every 10°C rise in temperature. Like Hfe as high as 360, when according to the data sheet it should be 34/115. synthrotek. Among germanium transistors, many type numbers (see the list below) are possible candidates for FF circuits and clones. Well they do, and for the money, they're great. Jul 31, 2023 · For a npn germanium transistor, the transistor will turn on when the positive probe is connected to the collector and the negative probe on the emitter. What you will find as you test more germanium is that locking down a specific hfe value is a crapshoot. 2N167 General Electric NPN Grown Junction 3. 472 volts per milliamp, so a milliamp of leakage will cause 2. Building a germanium-based Fuzz Face requires choosing transistors within specific hFE ranges for Q1 and Q2. L’étage de puissance fait appel à des transistors complémentaires PNP & NPN. com/article_folders/ffselect. blogspot. Easy to use and quick to get started The process supports design scales of 300 . Keen, which you should definitely read. It is a veroboard layout of the tester I read about on geofx. Test leaky 2N388 V BE forward biased voltage drop. Jan 31, 2021 · After improving my germanium transistor test kit yesterday, I thought I should also upgrade some dodgy leads I’ve been using with my breadboard. Test your transistors to make sure they don't leak like crazy, figure out a ballpark hfe, then go build something. I’ve tried a lot on the breadboard, and found that most work just fine. 4K resistor. They test all sorts of things, including diodes, capacitors, resistors etc. am I right Apr 27, 2021 · the RG Keen method for testing germanium transistors - link to instructions here; a cheap multi-function tester - link to tester here. Mar 15, 2017 · My small component tester recognizes the devices as Ge, but some of the readings it is spitting out are crazy. Jan 16, 2021 · TRANSISTORS: RG Keen, Germanium Transistor Test Method If you haven't heard of this before (which seems unlikely), here's the original RG Keen article , which explains how it works. // voltage, as this is an NPN transistor, we must subtract from the rail voltage to get leak // voltage leak_milliVolts = rail_milliVolts - collector_milliVolts; I saw a post on DIY Stompboxes where someone else was attempting to do this, but I never saw them complete it I knew one of the problems was that the ADC on the ATMEGA328P is kind of limited and prone to too much noise So I found a breakout board for the ADS1115 16-Bit ADC that was available and Std Edition. Supports simple circuit simulation For students, teachers, creators May 7, 2024 · An hFE of 461 is really high for a germanium transistor. Feb 24, 2016 · Ever hear about "leaky" germanium transistor and wonder how to measure that? Well, here's a little utility board that allows you to test germanium transistors. org, le schéma est lisible ! IL y a eu plusieurs versions de ce tourne-disque. Costs about the same as a decent multimeter and worth it. I’d suggest putting the two withe the lowest hfe up front for Q1 and Q2, and then the highest hfe with moderate leakage in Q3. Jul 26, 2019 · A priori, cet électrophone utilisait des transistors germanium type AC117P et AC175P, dans l’étage de puissance. 7 uA). as already mentioned, transistors are temperature-sensitive and germanium most of all. For Ge transistors, it will give you NPN/PNP, identify CBE leads, Hfe with test current used, Vbe with test current used, and leakage (critical for Ge transistors. Sep 28, 2011 · Here's how it works: put the DMM across the 2. ) Sep 20, 2012 · I'm planning to try vero or perfboard for the first time, specifically to set a germanium transistor tester per the circuit that Smallbear recommends. comHow to Test Germanium Transistors - We use these AC128 transistors in our Fuzz Face Clone Pedal Kit. Literally breathing on the transistor will drastically change the hfe, try it if you don't believe me. Down you get the leakage, and up you can get the gain. Aug 11, 2012 · measured something like 100 transistors with the germanium transistor tester (which thanks to Ivlark I built myself). DIY your own boutique effects! This is a germanium transistor tester. Mar 2, 2021 · In terms of transistors, MKIII Tone Benders will work and sound good with almost any germanium transistor. It explains pretty much everything going on in this process. 2N240 Philco PNP Surface Barrier (SBT). This tool should help you publication deals exclusively with germanium transistors, which were the first transistor type to be used in commercial and military computers. except for the few 2sa12s which were mostly very low leakage with hfe around 30,nearly all of them were of hfe's around 150 to 250. For example: At V CE of 5 V and 4th I B curve (representing I B = 27. Geofex's handy circuit can test both, so that's the way to go for me. Started by Bret608, April 10, 2013, 02:10:04 PM I am in the process of building the following GE transistor test circuit Aug 10, 2020 · I finally broke down and bought a Peak Atlas DCA55, and it's now my go-to for transistor, diode and LED testing. In this video, we'll demonstrate how to use an Arduino Nano, an OLED Display, and a 16-Bit ADC to tell if our Germanium Transistor is an NPN or PNP, how much I have a transistor tester on my DMM but without leakage measurement. I used a 2k and 470R in series to get as close to 2. These things are so cheap one could easily assume that they don't work. Silicon has been used, and many people like the harsher clipping, but it is a different sound. Simulate the PNP transistor test circuit in LTSpice… The PNP circuit is the same as the NPN transistor test circuit. http://tagboardeffects. Sep 17, 2018 · CORRECTION to the video: on 2. I have a couple of questions: 1) Are perfboard and vero the same thing? I'm thinking of just grabbing some with my next Mammoth order. An article posted by R. Put a transistor in the socket. If you’re just testing a handful of transistors, breadboarding RG’s circuit is probably the faster way to go.