Thursday, January 12, 2012

Constructing and Diagnosing Simple Electronic Circuits

Using the 5VDC power supplies/transformers that we constructed during the previous session, we powered various simple circuits to demonstrate and understand Ohm's Law and the practical uses of bread-boarding circuit diagrams before building on a macro scale.

Upon completion of building a simple circuit with an LED and a resistor, Prof. Mason would then create a break in the system and we were tasked with diagnosing and repairing the fault. The purpose was to demonstrate the bane of most electronic circuit failures - no continuity. We were then instructed in the methods and applications of multimeters to check circuits for continuity, resistance, voltage and amperage.



In observing the difference between regulated vs unregulated power supplies, we were assigned with devising a method of using a resistor to create a load on a live circuit and then determining if the total available voltage decreased. In the case of our switching 5VDC power supplies, it did not.

Much magic smoke was released into the atmosphere on this evening.




Finally, to understand variable resistors (potentiometer) and "forward voltage" in LED circuits 
(which Prof. Mason was delighted to explain to me)
the simple circuit below was constructed with a linear potentiometer, a 100 Ohm resistor and a red LED. Consequently, this also demonstrated the logarithmic gain inherent of LEDs.



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