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A Multimeter is the sure fire way of telling if metal thingie one is connected to metal thingie two.
 
A Multimeter is the sure fire way of telling if metal thingie one is connected to metal thingie two.
 
A Magnifying glass also helps if you are trying to see quite where the tiny bit of solder has bridged between two tracks on a piece of stripboard.
 
A Magnifying glass also helps if you are trying to see quite where the tiny bit of solder has bridged between two tracks on a piece of stripboard.
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===A Multimeter ?===
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Yes, the essential first purchase after the soldering iron.
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At minimum it will measure three things
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====Voltage====
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The potential difference in Volts between two points.
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Selected with a V Dc or Dc Volts setting on the control knob.
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A battery is an obvious example. You will see them with voltages from half a volt up to 20 Volts and more. The meter will show you the voltage.
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Reerse the leads notice the display now shows -20Volts. You are measuring the difference between two voltages, even if one of them os at 0V and attached to all the metal around you. Volts are always about differences.
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====Current====
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No of electrons flowing per second
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It might be tempting to simply put the meter when set to amps across the battery we measured in Volts, but this is not a good idea. A current measurement is measuring how many electrons are flowing. And if we do this with a voltage we have just measured are then we are effectively connecting the two voltages together and as much electricity as can will flow. A SHORT CIRCUIT!
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Since our the electronic we have constructed does not behave like a short circuit (Hopefully!) then there must be something limiting the current. V= IR, Resistance ! The Next measurement .
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So in small electrical circuits we tend not to measure too much current, because it normally involves breaking a wire to perform the measurement. Measuring current consumption of a Pi can be an indicator of problems but ensuring a reliable way of actually making the measurement with a Pi & a Multimeter can get rather involved. Best measured on a Bench Power Supply. The net purchase. . .
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But I digress, The Pi acts as a resistance and using the two equations of electricity
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'''V=IR      Voltage (Volts)  =  Current(Amps) * Resistance (Ohms) '''
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&
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'''W=VI    Power (Watts) =  Voltage (Volts) * Current (Amps) '''
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Looking at the Zynth here I'm dring it from a 12V power supply into a hifiberry Power Amp Card.
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My Bench top power supply shows a voltage of 12.27 Volts, 0.460 Amps and 5.656 Watts
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The Maths checks out (fairly closely  to an engineering accuracy)
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12.27 * 0.460  = 5.6442
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So it's right to about two decimal places 9 this is a whole area in itself...)
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So we know the Pi is consuming 5.6 Watts of power.
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And here's the clever bit. A Pi runs from 5V  so we can calculate the Current flowing into the Pi by playing with the same equation again.
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W = IV
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5.64 Watts =  Current * 5 Volts
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So the current = 5.64/5  = 1.128 Amps
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====Resistance====
    
==How does the zynthian understand the encoders?==
 
==How does the zynthian understand the encoders?==
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