Patch Cord Analyser Revisited - Materials Diagram

[Fay Reid]

On the diagram, keep in mind that when following the circuit, the current continues from one ground on a particular jack to the ground on its other side. It's all one part of the jack...the sleeve which contacts the shielding mesh terminal of the patch cord. The grounds on the two jacks are connected only by the shielding of the patch.

A short in the patch cuts from the center wire of the patch to the shielding, thus eliminating the "B" led from the circuit so it won't light.

If one of the wires in the patch becomes broken or unsoldered from its terminal, an effective "switch" has been opened so no current flows and neither bulb lights.

Led's are not required for this project. They're simply readily available, cheap, ecofriendly, sturdy, and easy to work with. But they must be soldered into the circuit with their correct terminals effectively connected to the positive side of the battery in the circuit. I have forgotten some/most of my university electronics so can't at the moment give the correct terminal, long or short (L or S on the diagram), which connects to the positive side. I think it might be the long terminal. However, it's relatively simple to determine the correct one. Connect an led in series with a resistor and a cell or battery. (Always include a resistor in this circuit since the led diode has very little resistance so will overheat and burn out with the high current.) If the led lights, note the relative positions of the led terminals in relation to the positive side of the cell. If it doesn't light, reverse the battery terminals. If it still doesn't light, you've got another problem entirely. At any rate, when the led lights, note its relative polarity in the circuit. Transfer your findings to your analyser project.

Now you can make a vinyl sleeve cover for the analyser to protect the slightly protruding led's. Cut out a rectangle of material of the proper size. Fold it in half such that the vinyl sides are in contact. You are sewing it inside out along one end and one side leaving one end open to insert the analyser. Now, turn the sock vinyl side out. If your measurements have been fairly accurate, the seams (now on the inside) will be flattened slightly to help hold the sock on the analyser. This idea can be used for many of your other trinkets in your suitcase or pack-a-seat. These cases help to signify if anything is missing; a case without something in it is a lonely case!
Fay

[Fay Reid]

[richard burton]

But why, when you can just go down to your local hardware store and buy a Multimeter, for less than the cost of a Big Mac ??

[Fay Reid]

I agree, Richard. I have at least a couple of multimeters lying around that I'm using for one thing or another on a not-too-regular basis. The analyser might get used once in ten or twenty years, so I wouldn't be building it for any practical purpose.

The exercise is in the pride of building something and the educational experience that is gained. This knowledge may be use for many other practical applications. There isn't an appliance around the house that I haven't repaired to some extent; washer, dryer, refrigerator, stove, radio, tv, tape recorder, automatic garage door opener, session 400, car engine and many under the dash problems, farm tractor engine overhaul, and on and on. With each problem that is solved I'm finding that the next problem is easier to deal with. Life is the knowledge that is gained along the way. I wouldn't consider myself a particularly ambitious person and others would find me the same, since I'd rather help another person with a problem than with some physical task of one kind or another. In the latter case, I've been there, done that, but I'd rather be solving a problem. It's just my make-up.