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some very noob questions (how to ground?)

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  • some very noob questions (how to ground?)

    hello, i'm building a basic boost circuit as a first project to build some experience reading a schematic. numerous times the plan calls for a ground, with that dashed-arrow symbol. how do i handle this?

    here is the schematic:



    2- another question I have is how to handle the top bit. is that the positive side of the 9v battery connector going off into the circuit while the negative side goes down to the input?

    3- also, how do i connect the wires to the input/output? there are 3 little connection spots on the 1/4" inputs that I have, and the schematic doesn't saw which side is connected to what. does it matter?

  • #2
    also, how do i install the 3 prong transistor? there is no indication on the schematic or the component itself. concerning its orientation.

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    • #3
      All the grounds must be connected together and connectied to the input and output jack grounds.

      The input jack is a stereo jack, the negative side of the battery goes to the second channel terminal. When you plug in a mono plug that terminal will be grounded thus turning the circuit on.

      The package the transistor comes should have the pinout on it and will be labled emitter, base and collector. The line inside the transistor symbol is the emitter the line it intersects with is the base and the line going out the other side is the collector.

      David H

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      • #4
        Thanks for your help. I finished this project, and it works. However, I get significant volume drop when it is engaged, and no disortion/grit. I'm just calling this one a failure-- it was the first time I had even soldered anything, so I certainly learned a few tricks here.

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        • #5
          1. The circuit has a common, which we like to call ground. The ground symbol is used instead of drawing ground wires all over the drawing. ANything with the ground symbol is connected to the same wire or trace.

          2. The negative of the battery goes to a contact on the input JACK, but not to the input itself. That jack is a TRS jack - Top Ring Sleeve - often called "stereo" jack. The battery negative is wired to a contact that would normally touch the ring of a stereo plug. Like on your headphones plug, that extra band near the end. But in plain old mono guitar cord plugs, the shaft of the plug - the sleeve - will touch that contact, and complete the circuit to ground. That way the battery is not connected until something is plugged into the jack.

          The drawing of the jack represents it mechanically. The grounded narrow rectangle is teh barrel of the jack. Note the two contacts: one is closer to the barrel, while the other is further in. That further in one is the tip of the plug contact, while that ring cointact is closer to the barrel. They don't number the contacts or anything because there are dozens of different jacks yiou could use, and they are not all shaped the same.

          3. Eyeball the jack and what parts touch what on the plug, then you can determine which wire goes where. yes, of course it matters, each terminal does a different job.

          (4.) They list several transistors, most any small signal transistor would work. The three legs are collector (C), base (B), and emitter (E). On the drawing, the top leg of the transistor is the C, the left one the B and the bottom one the E. Not all transistors have the same order, so they don't include a picture. But the symbol on the schematic tells you which leg goes where.

          Most small transistors are flat on one face and rounded on the far side. The flat face is the front, where the lettering is. Look at the front. Left to right the three legs...

          Well, all the ones with numbers starting 2N... like 2N5088 are left to right E-B-C.

          Any with numbers starts 2S... like 2SC1684 are left to right E-C-B.

          And I don't remember which way the BC ones go, I have to look it up every time.

          If i had to guess, I'd say the reason it didn't work well was you wired in the transistor wrong.
          Education is what you're left with after you have forgotten what you have learned.

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