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Hello! (and Help!)

Discussion in 'General Electronics Discussion' started by McCall, Sep 11, 2012.

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  1. McCall


    Sep 11, 2012
    Hi Folks,

    I'm new to the forum :) I searched the Internet for an electronics forum and this seemed the nicest one. I've joined because I'm currently making a small project as part of getting my next amateur radio license. The requirements are:

    10d.2 Demonstrate the ability to make good soldered joints.
    10d.3 Construct a simple circuit containing a battery, resistor, LED, lamp and switch.
    10d.5 Demonstrate that a diode will only conduct in one direction in a simple DC circuit.
    10d.6 Demonstrate that a transistor can be used as a switch in a simple DC circuit.

    There are others requirements for the license, but these are the ones I thought I'd try and cover in one simple project. I plan on using stripboard, and I have a host of components already. from things I've done with Arduino's.

    So far, I've been working on a breadboard, and have a 2N4401 switching an LED on and off based on + input on the collector. I'll add a diode to this circuit to show they only allow current to flow one way.

    I was thinking of using a 555 (as I have some spare and always wanted to use one) to input to the collector from a different circuit to activate the transistor and turn the LED on and off. This second circuit could be turned on and off via a slide switch (which I don't have yet).

    The final part is a MES bulb connected to the power rails to show if its on or not.

    I've done a diagram in Fritzing, and I was wondering if anyone could help me check if it would work or not. I've never designed a circuit, or used Fritzing, so I am very sorry if this is poor.

    I've attached the images, and my Fritzing file is available here.

    Please can someone help me a) with Fritizing as my diagram looks rubbish! and b) advise me if the project will work anyway? I think I understand what I want to do, but I'm not sure if my implementation is sound or not.

    Thanks in advance!

    Attached Files:

  2. CocaCola


    Apr 7, 2012
    What a mess, you really need to spend a little time getting that schematic in order, move parts around and get all the connections made... All the unrouted connections make looking at it very hard and there is no way it's going to work with so many connections not made even if the idea is solid...

    Your switch alone will cause an immediate short and kill the power source the way you have it hooked up...
    Last edited: Sep 11, 2012
  3. duke37


    Jan 9, 2011
    Draw two horizontal lines, one at the top of the diagram and one at the bottom. Connect the positive of the battery to the top line and the negative to the bottom line.

    Find the 555 data and fit it between these lines. Put the output on the right.
    If you get the diagram laid out logically, then the circuit is much easier to understand

    CDRIVE Hauling 10' pipe on a Trek Shift3

    May 8, 2012
    You don't need a 555 to do any of the things in your list.

    Is this a Novice license?
  5. McCall


    Sep 11, 2012
    Its the UK Intermediate License. I know I don't need the 555 - but I was thinking it was a nice way of applying power to the collector on the transistor.

    CDRIVE Hauling 10' pipe on a Trek Shift3

    May 8, 2012
    It's hard to comment on that because as CC said "It's a mess". Over complicating a circuit doesn't make it better or "nice" though. Since you're in the UK you may not know who Rube Goldberg was. You may want to Google him. ;)

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