I built some circuits last week, simple ones

    Introduction: This is how we wire an individual circuit; a series circuit; a parallel circuit; and a compound circuit. Any interpretation following is purely my understanding of what is really going on in any of those circuit. Big THANKS to bigmitch, for opening my eyes about electricity. Here we go.

    We all know the drill: get a circuit board; enough wires; a multimeter. First of all check the probes for resistance, then check the supply for 12V, check if we got fuses installed( if we run out of fuses because we accidently short our circuit; we'll have to direct it, and make it right, and hopefully we won't blow anything on the wall). All done? Now lets get into the circuits.

   1.INDIVIDUAL CIRCUIT
Nothing special here really: Pos+; fuse; switch; bulb; Ne-. The key thing is  we try one with big bulb and then with small bulb. We were assigned to identify the change in current measure in the circuit if the resistance change: Small bulb-0.33A; Big bulb-0.72A. This explain that the small bulb lights less because it has greater resistance, which cause the current to be lesser hence smaller wattage than the big bulb.



   2. SERIES CIRCUIT.

    This is the difference between series and individual: the current change. In series, the current runs through any part of the circuit is the same. But voltage shares, V=IxR, therefore, the smaller bulb will draws more voltage. If u have 2, or 3 identical bulbs, voltages are the same for all. If u have a series of different bulbs, the bulbs with most resistance with draw the most voltage, and then same goes for the 2nd largest, 3rd largest.
    But also in series circuit, the more bulbs you add, the more the total resistance increases( Rt=R1+R2+R3+...+Rn), hence the more the total current decreases, and the result is dimmer for every additional light bulb as well as all light bulbs.
   3. PARALLEL CIRCUIT.

   We built a parallel circuit with 2 bulbs, and then we measured available voltage at each light bulbs, we got approx~ 12V for both. Also; voltage drops across each bulb is 12V. This indicates that the voltage rule for parallel applies here. Force from the supply is endless and there's no stopping when it has 2 ways to push. For the Amps readings, we got 0.73 for each bulb and supply current of 1.46. This means that currents from + travels to junction then splits up 2 ways distributing to each bulb, and then they come back and add up again, as Kirchoff Law states: Total I in= Total I out.
   In parallel circuit, the brightness of each bulb is maintained since each branch is an individual circuit. And because AV is preserved for each, the branch current is also maintained by only being affected by its own bulb resistance, therefore, the brightness is maintained.

  4.COMPOUND CIRCUIT.

This is when all the fun kicks in. We were supposed to wire 2 parallels and 1 series following, and all 3 are big bulbs. But somehow, the two parallels didn't light up as they supposed to, only the series bulb. So we decided to wire the 2 parallels using small bulbs, here is the result:

  Available Voltages(AV) through both bulbs are both 12.6V, and after are both 5.25V(approx~). This tells us that VD across both bulbs are about 7.35V, so 7.35V is comsumed by the parallel circuit, only 5.25V left for the big bulb. Why? Because small bulb has higher resistance(approx~ tripled the R of the big bulb), therefor the whole parallel compound's resistance is just happened to be larger than the big bulb stands alone, hence draws more voltage.

5.REALIZATION

   U see parallel is way better than series circuit because of no matter how many light bulbs you wire there, the voltage across each one of them is the same, the more you wire, the less total resistance you have. And the cool thing is the current doesn't drop for any additional bulb installed.
   In the experimental compound circuit we tried, we add one more bulb in series:



We can see clearly how a parallel brightness is worsened by adding series. More bulbs means more resistance as the total current drops, the voltage through each bulb also drops, leading to overall downfall of brightness.
So in conclusion, series circuit of consumers is not an effective way for optimal operation, but parallel. A series circuit in series to a parallel circuit sabotages the normal operation of consumers component in the whole circuit.
Because of its nature, parallel circuit is the main circuit for bits and pieces on your car. Multiple lights, countless switches,.etc..ưhich can only be met by parallel circuits.