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Model Train Track detector Updated twin-t model train track detector circuit parts list? Answered

Model Train Track detector
Does anyone know what the parts are for this updated twin-t model train track detector circuit?
See Fig. 5-5 in "Easy to build Electronics Projects for Model Railroaders"I checked twice with the publisher for the missing parts list in the article but never got a reply.
C1 - ?? , C2 -??, D1-D6 - ??, D7 - ??
Q1,Q2 - TIP 142
R1 - ??, R2 - ??,R3 - ??
Thanks, AB

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steveastrouk (author)2010-08-05


All the diodes 1N4007
C1,C2 o.22uF or bigger, but not electrolytics.
R1,R2 - try 1K
R3 guess at 2K2

Its hard to read the functions of the pins, so R3 may need some experimenting.

Steve

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steveastrouk (author)2010-08-01

Put the circuit up, and I'll take a guess.

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brownart (author)steveastrouk2010-08-05

Thanks everyone for your replies. I am sorry that I did not make my request clear. I have attached the circuit for which I am trying to find the values, the article did not contain the normal parts list for this circuit. I know that Q1 & Q2 are TIP 142 transistors or I can use the smaller-case TIP 120s. The unknown capacitor (C1 & C2) values, the unknown diodes (D1-D6) values and the unknow values of resistors(R1-R3) are what I was hoping someone could provide and had already built for their train layout. AB

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NachoMahma (author)lemonie2010-08-01

.  ... and Q is usually a transistor.
.  TIP 142 is a power transistor. Google is your friend.

.  You really need to post a link to a schematic (or, at the very least, a parts list) for ppl to be able to help much.

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lemonie (author)NachoMahma2010-08-02