Experiment No.1 Resistors

Resistors and circuits

Stuffs: Supply voltage, electricity, types of circuit, components n junctions method, multimeters...

Laws: Ohm's Law, Kirchhoff's Law...

Elements: Voltage, Current, Resistance, Power...

Lets start with voltage: In order to start a circuit we need a supply voltage. There is a definition called "Potential Difference". This is the voltage difference between the positive n the negative of the battery which is hooked up in a circuit. This can be visualize as water from a high reservoir to a low reservoir, when gravity will pull the water down if connected through a straight pipe visualized as electrical wire. 

If wire conducting electricity is visualized as water flowing through a pipe. Then adding resistors is just like narrow parts of the pipe restricting flow. Which leads us down to explaining how resistors work in series or parallel circuit. In series, adding resistors is like having more narrow spots along the pipe, so in the end our water flows slower n slower. So hence we have: R total = R1+ R2 + R3....

In parallel, we notice that total resistance is calculated using a weird formula: 1/Rt=1/R1 + 1/R2 = 1/R3....Well imagine this: first we have a pipe with 3 narrow spots, then instead of using that, we have 3 similar pipes similar to the first pipe and each have 1 narrow spot equivalent to the first pipe, and let the water flow. So in truth we have a pipe that is 3 times bigger than the first pipe that the narrow spots hardly count anymore.  And that can be understood as by adding up resistance in parallel, total resistance actually proportionally decreases.

Continuing with the water pipes n reservoir, if supply voltage is visually considered as gravitational force, then is it different in each pipe when pushing down the water? NO! They will have the same flow, the same push as well as same current and available voltage through each branch. Don't believe me? Look at what we did:
   2 resistors  color code reads 270 Ohms 5% (red, violet, brown, gold) and 470 Ohms 1% (yellow, violet, brown, brown): measured result 267.7 and 471.3.
I put one end of this to another, and put an Ohms meter across the whole junction, I got 737 Ohm, didn't they just ADD up?
  When I put them in parallel, I would expect the total to be less than either both of them, and I got 170.8 Ohms. I check with the weird formula, flip it around: so Rt=(R1R2)/(R1+R2); (267.7x471.3)/ 737= 170.8 Ohms. So the result in theory which was Ohms law application is reasonably match the practical result.