P. Supply, F. Generator... what next?

Discussion in 'General Electronics Chat' started by adam555, Dec 5, 2013.

  1. adam555

    Thread Starter Active Member

    Aug 17, 2013
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    When people start with electronics, most often than not the first mayor practical project they take on is to build their own power supply. Then, though not as usual as with the power supply, many people build a function generator; which I just finished. So I'm currently looking for a new project, and I'm wondering: what's next?

    Obviously, there is no right answer to this question; it's all down to personal preferences, needs, and means. So, what I'm asking is: in general, what do you think beginners build after the power supply and the function generator? or if you prefer: what was next for you?

    Not really asking out of curiosity, I'm looking forward to start a new project and will welcome any ideas or advice; so thanks in advance for posting.
     
  2. MaxHeadRoom

    Expert

    Jul 18, 2013
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    For me it was a universal Tube tester, including (re)winding my own transformer for all the different tube filament voltages.

    But I imagine this won't be high on your priority list? ;)
    Max.
     
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  3. adam555

    Thread Starter Active Member

    Aug 17, 2013
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    Probably not. :)

    I also just finished building a battery charger, which now sends voltages and temperature to Arduino and prints them on an LCD display, and which also connects to Processing 2 to output a graph on screen... it's quite cool actually, but doesn't really count for what I'm asking

    I was looking for something a bit more complex, of a more general use, and common in any hobbyist's lab.
     
  4. hexreader

    Active Member

    Apr 16, 2011
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    Frequency Counter?

    ... or scope?
     
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  5. wayneh

    Expert

    Sep 9, 2010
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    Coming from the sciences, I've always had a thing for instrumentation or "interfacing" electronics to the real world. Sensors, telemetry, data acquisition and control, and so on. This is especially interesting these days when everyone is carrying a supercomputer in their pocket. There's no longer any reason to build a brain into an instrument - you just need to interface a sensor to your iPhone and let it do all the processing.
     
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  6. adam555

    Thread Starter Active Member

    Aug 17, 2013
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    That's a great idea.

    I did one for the function generator but it doesn't work that well. What method do you suggest -the one I did was with a multivibrator and decade counters-.
     
  7. adam555

    Thread Starter Active Member

    Aug 17, 2013
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    Many of the circuits I did would be far easier, quicker, cheaper and probably better if I just used Arduino (e.g. I can easily do a better frequency counter than the one mentioned above); but I think that one of the most important parts of building your own electronic gadgets is to learn with the experience. You don't really do that by programming everything with a microcontroller or an iPhone; so I usually avoid it, unless I have no other option.

    In any case, I don't have an iPhone or Android... I'm still stock with my old Windows Mobile phone; which is basically a hybrid between phone and PDA. :p
     
  8. hexreader

    Active Member

    Apr 16, 2011
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    Sorry, I was thinking micro-controller project, but now I see that you are thinking without micro-controller.

    Can't think of any useful non-micro test equipment projects that are worthwhile.

    Sorry to waste your time.
     
  9. davebee

    Well-Known Member

    Oct 22, 2008
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    I'd recommend a project which I built many years ago and still use.

    This was originally just a hacking-around project, but it has proved its usefulness over and over and over again over the years.

    Build a string of cascaded counters that feed seven-segment decoders, then connect them to drive seven-segment LED displays. Build a diode-protected, Schmidt-triggered input to the counters. Add a reset button for the counters, and add a simple LED to indicate the input logic level.

    How many counters and LED segments you choose to cascade is up to you; I only used three LED segments, but I'd use six or more if I were to rebuild this device.

    This simple thing lets you test all sorts of logic circuit issues very easily.

    Is an oscillator oscillating? Connect it to the counters and see if the counters increment.

    How fast is it oscillating? with enough LEDs, you can estimate frequency to within an order of magnitude, which is often all you need.

    Is a given logic point high or low? Look at the level LED.

    If you're designing more complex logic that needs to emit exactly 8 or 32 or 512 pulses, feed the output to your device, let your circuit under development run for a cycle and read the digits.

    And it's so simple that it's easy to build.
     
  10. adam555

    Thread Starter Active Member

    Aug 17, 2013
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    Not at all. In this case, since frequency counters are rather a must in any lab, and since these are better with micro-controllers, if I'm going to build one for general use I think it would be best to do it that way. Just that I'll probably leave it aside until I start practicing with individual micro-controller IC and buy the programmer.
     
  11. adam555

    Thread Starter Active Member

    Aug 17, 2013
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    I like your idea; thanks.

    I could probably build it within the frequency counter -in just one device-; then add a switch to choose between decimal and frequency counter.

    I don't think it would be too difficult to do; and most components could be shared between both applications.
     
  12. PackratKing

    Well-Known Member

    Jul 13, 2008
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    Being a hopeless addict to tearing broken things down to " autopsy " them and figure why they died, and re-engineer the problem if necessary to make repairs...

    I worked in a textile mill last century :p [ Polyester Double-knits ] and one of their analytical tools for the machines, was a rapid fire 0-20,000 flash/second Xenon strobe, triggered by a VCO, to do stop-motion studies... however ...

    I have beau-coup experience with xenon strobes doing photo-equipment repair, though since the advent of the brilliant white LED, which has an adequate rise/fall time to imitate a strobe circuit, involving far less high voltage circuitry, I was going to build along that line...

    Or cobble up a digital tachometer for my lathe... on that note, you'd love my electronic dial indicator, based on a potentiometer and a digital ohmmeter.

    Building things is fun, tho' being retired, I find that I must have my efforts in whatever, actually generate some cash enhancement to the ol' SS to live on, so time for R&D is slim.
     
    Last edited: Dec 6, 2013
  13. adam555

    Thread Starter Active Member

    Aug 17, 2013
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    I know exactly what you mean; always been like that since I can remember. Though in my case after the "autopsies" the patients tend to stay dead beyond any hope. :p

    I also need to cut down on the time I dedicate to learning electronics and do some work; which is harder than it sounds when you don't have a boss "motivating" you. On top, so far for me electronics is like a bottomless pit that keeps on taking money and gives nothing back. :(

    But I can't stop this urge to build things with the little knowledge I gathered; it's so strong that, for lack of better projects, I've already re-build the function generator 3 time -and I'm currently hand on the fourth modification-.
     
  14. ScottWang

    Moderator

    Aug 23, 2012
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    You can easily to buy a Frequency counter, but if you want to build one then you will learn a lots of logic control circuit.

    Frequency counter -

    1. CD4543*2,CD4553*2 : 6 digits decimal counter.
    2. 10Mhz crystal oscillator : the 10Mhz for the timebase oscillator.
    3. 74HC390*1 : one part for increasing the measuring range, another one for dividing the timebase.
    4. CD4518*3 : divide the 10Mhz crystal oscillator to other timebase as 0.1Hz, 1Hz, 10Hz.
    5. Designing the circuit of reset and strobe, and timebase control.
    6. ...

    If you want then you can adding some more as measuring the high low duty cycle ...

    LED display 6 digits decimal counter on page 7.
     
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  15. PackratKing

    Well-Known Member

    Jul 13, 2008
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    On that note, I took to heart an admonition of the "amateurs' code" printed on one of the first flyleaves of my 1976 edition of the ARRL amateurs handbook...point 5...

    It States: " The Amateur is balanced... Radio is his hobby...He never allows it to interfere with any of the duties he owes to his home, his job, his school, or his community."

    Sometimes though, I find I have to put my foot down and just let the others know that what I am doing, educates me so that I can be more productive... a real balancing act...:p
     
    Last edited: Dec 6, 2013
  16. adam555

    Thread Starter Active Member

    Aug 17, 2013
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    I'm pretty bad at time management (even though I did a university course just on this subject); always end up doing whatever I find most interesting in each moment, and forget about everything else. Sometimes I even forget to eat and sleep. It's said that Newton also used to behave in this way when he was in his laboratory; so, if it wasn't bad for Newton, I guess it won't be bad for me. :D

    Fortunately, my source of income kept me quite interested for 3 years, just before electronics; though, now that I need to do it by force is not the same thing. :p

    I'll have a try at different methods for the frequency counter; but I do want to do it myself, and learn something, instead of buying it.

    The one I did for the function generator was with a CD4047 multivibrator -which provided the clock for counting the cycles- and then one CD4026 decade counter for each digit. It doesn't work well, because if I want it to measure the low frequencies I need to set the multivibrator also at a low rate, which makes the displays blink.

    In any case, so far everyone recommends micro-controllers for this task; though I would prefer something like what you propose. But as I said previously, I'm leaving this project for when I start with digital electronics and micro-controllers.
     
    Last edited: Dec 7, 2013
  17. tindel

    Active Member

    Sep 16, 2012
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    Another couple things that come in handy in a lab that I haven't seen mentioned are 1) a resistor load box 2) a capacitive load box, and 3) a electronic load.

    All of these are pretty easy to make.
     
  18. MaxHeadRoom

    Expert

    Jul 18, 2013
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    One thing i made for a buddy that is in the TV repair Bus. is a HOT/Flyback transformer ringer, just has a simple LED bar graph to show the if the suspect is shorted.
    Max.
     
  19. adam555

    Thread Starter Active Member

    Aug 17, 2013
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    [​IMG]

    Never heard of those boxes; thought this is more or less what I found on the internet.

    Are they for measuring the impedance and capacitance of a circuit's input/output?... I'm kind of interested; so, could you please explain a bit more?

    Actually, now that you mention it, I need to build some sort of device to measure capacitance and inductance. Anyone knows of a simple design for a circuit that does both -preferably without using microcontrollers-?

    Also don't know what that is. But for now I'm not planning on doing TV repairs.
     
    Last edited: Dec 8, 2013
  20. ScottWang

    Moderator

    Aug 23, 2012
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    To make the Resistors Box, capacitors Box, what you see is what you get.
     
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