Dazza Posted October 15, 2004 Report Share Posted October 15, 2004 :)here it is the in circuit transistor tester. ill re photo the circuit better and put it in as soon as i find the circuitSteven, I would really like to put that transistor tester together 8). have you already posted the circuit for it somewhere, or are you still, to find it to post :). Quote Link to comment Share on other sites More sharing options...
steven Posted October 15, 2004 Report Share Posted October 15, 2004 :)mozikluv which transistor tester are you refering to ive uploaded 2 i think but the one i biult from a kit is the best one to biuld as it works by shorting out the leds Quote Link to comment Share on other sites More sharing options...
Dazza Posted October 15, 2004 Report Share Posted October 15, 2004 Yes steven, the one you posted from a kit ;D. Quote Link to comment Share on other sites More sharing options...
steven Posted October 15, 2004 Report Share Posted October 15, 2004 :)dazza have you allready seen the posting of my in circuit transister tester i uploaded before, it works really good to, not bad fro a kit, Quote Link to comment Share on other sites More sharing options...
Dazza Posted October 15, 2004 Report Share Posted October 15, 2004 steven, it looks good. But I want that Dick Smith one ;D ;D, or is that it you posted on this page Quote Link to comment Share on other sites More sharing options...
steven Posted October 15, 2004 Report Share Posted October 15, 2004 dazza i posted that dicksmiths one a while ago if you cant find it ill find it for you Quote Link to comment Share on other sites More sharing options...
steven Posted October 15, 2004 Report Share Posted October 15, 2004 its under the topic in circuit transistor tester, dazza Quote Link to comment Share on other sites More sharing options...
steven Posted October 15, 2004 Report Share Posted October 15, 2004 :) page 3 of electronic project/ design ideas you will find my in circuit transistor testor the dazza Quote Link to comment Share on other sites More sharing options...
Dazza Posted October 15, 2004 Report Share Posted October 15, 2004 Thanks steven, I found it :). Quote Link to comment Share on other sites More sharing options...
steven Posted October 15, 2004 Report Share Posted October 15, 2004 dazza ive posted other tesor units before, allso includeing the logic ic tester, check it out Quote Link to comment Share on other sites More sharing options...
steeve Posted March 13, 2005 Report Share Posted March 13, 2005 helloi have built the transistor tester , and it work , i've followed the revised schematic .if anyone want it , i have made a pcb with expressPCBhere's the file Quote Link to comment Share on other sites More sharing options...
MP Posted March 14, 2005 Report Share Posted March 14, 2005 It is a shame that you made it in ExpressPCB. No one will be able to make the board except ExpressPCB. Do you have them make all your boards or is there a trick to getting it to print out a board pattern so that you can make your own?BTW- Your file did not attach.MP Quote Link to comment Share on other sites More sharing options...
audioguru Posted March 14, 2005 Report Share Posted March 14, 2005 C'mon Steeve,Post the pcb so we can get the project corrected (its 4027 still has its clock pin grounded) and nicely completed.http://www.electronics-lab.com/projects/test/008/index.html Quote Link to comment Share on other sites More sharing options...
giroup01 Posted February 14, 2006 Report Share Posted February 14, 2006 My first project from this board! Works great! Built Manhattan style. Sorry for the poor picture quality though... Quote Link to comment Share on other sites More sharing options...
steveco1 Posted August 11, 2006 Report Share Posted August 11, 2006 Hi all. As you can see this is my first post having stumbled across this site just recently. I am a relative newby to electronics as well and need some help with this tester. I had all the discussed problems ( 1 LED on all the time etc.) but this was completely solved by the changes given by audioguru. My problem now is that the circuit will identify an NPN or PNP tranny, but will not show whether shorted or open - on a confirmed shorted NPN tranny, the NPN LED still just flashes. Anyone have any idea if I have maybe damaged the 4027, or is this another fault in the circuit? Your feed back will be very much appreciated.Steve. Quote Link to comment Share on other sites More sharing options...
audioguru Posted August 11, 2006 Report Share Posted August 11, 2006 Hi Steve,If the tested transistor is shorted from collector to emitter, then two diodes in series will be across each LED. Two diodes limits the voltage to 1.3V but a LED needs 1.7V or more to light so the LEDs will not light.If the tested transistor is open then the LEDs will flash like it is not there. Quote Link to comment Share on other sites More sharing options...
steven Posted August 11, 2006 Report Share Posted August 11, 2006 :)the 2 leds will flash if you have no transister being tested hooked up to it and if you do and they flash then the base and emmitter is shorted out on the transister you are testing Quote Link to comment Share on other sites More sharing options...
steveco1 Posted August 11, 2006 Report Share Posted August 11, 2006 Audioguru, steven thank you for your replies. I have exactly the results as you both describe if I physically dead short the legs - but I have a tranny that measures as follows with a multimeter:NPN Tranny :B-E = .708V B-C = .709 C-E one way = .5V C-E the other way = clear, B-C reverse polarity = 1.05V. Surely B to C should only read one way? If I test this tranny in the tranny tester it behaves as if the tranny is good! Why is that? Quote Link to comment Share on other sites More sharing options...
steven Posted August 11, 2006 Report Share Posted August 11, 2006 :)if you are looking at the tran sistor testor i posted some time ago in the forums somewhere it operates by shorting out the leds or something like that , im no exspert in the technicle exsplanations thing but biuld it, if it works its good enougth Quote Link to comment Share on other sites More sharing options...
steveco1 Posted August 11, 2006 Report Share Posted August 11, 2006 Can anybody help me with the above question? Is the tester maybe not 'sensitive' enough to detect a partial short as in my example? Quote Link to comment Share on other sites More sharing options...
steven Posted August 11, 2006 Report Share Posted August 11, 2006 :)its easy for a short to be tested as a short but for partial shorts ive never herd of a partial short Quote Link to comment Share on other sites More sharing options...
audioguru Posted August 11, 2006 Report Share Posted August 11, 2006 The transistor tester circuit is too simple to make a detailed test. It doesn't even test the current gain of the transistors. Quote Link to comment Share on other sites More sharing options...
steveco1 Posted August 11, 2006 Report Share Posted August 11, 2006 Hey I said I'm a newby - I don't know how to explain a leaky transistor between base and collector other than as a partial short. Anyhow, my real question has still not been answered - does anybody who has built this tester know if it does indicate whether a tranny is leaky or have I done something wrong with mine. As I said earlier, if I dead short the tranny at the legs it performs as indicated on the circuit diagram description - but with this transistor reading both ways between base and collector it doesn't pick it up. I know its not that important guys - but I'm trying to learn.Any suggestions?Steve. Quote Link to comment Share on other sites More sharing options...
steven Posted August 12, 2006 Report Share Posted August 12, 2006 :)sorey my transistor testor only tells shorts thats all and thats all i need to know Quote Link to comment Share on other sites More sharing options...
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