Sunday, June 13, 2010

AC sinewave

1. R.M.S what is it? : R.M.S stands for the route mean square, so we times the peak value X .707 to calculate the R.M.S.

2. what is the peak? : the peak is the positive of the sine wave whereas the trough is the negative of the aforementioned sine wave.

3. what does peak to peak mean? : if we are using a 50 Hz device its peak to peak would be 650 V because the peak and trough are both 325 V so we just add them together.

4. what is the frequency? : frequency is the amount of wave lengths (or revolutions) per second. so 50 Hz means  50 times per seconed.

5. what are wave lengths? : the length of a single wave is 360 degrees.

Sunday, May 30, 2010

worldcup spread sheet

Here is my spreadsheet

4 rules of flux lines

1. they always radiat from north to south.

2. they never intersect.

3. they cant be broken.

4 they always try to shorten themselves.

Sunday, May 23, 2010

what will the test tommorow contain?

i think these 8 topics will be covered.

1. vectors
2. resistor color code
3. E 12 & E6 range
4. multimeter comparison
5. conductors
6. temperature equations
7. networks
8.Si units

Sunday, May 16, 2010

Resistor network

 If R1 = 97Ω,
R2 = 41
Ω, R3 = 9Ω, R4 = 8Ω, R5 = 6Ω, R6 = 54Ω,


This is a Resistor Circuit, to find the total resistance you:

1. redraw circuit, add R3,R4 and R5 together so you have one resistor in parallel with R2.

2. calculate the combined resistance of R2 and R3 (made up of the old R3,R4 and R5) by placing them both under one and adding them.

3. find total current, V/R=I

4. use ohms law to find any other value required.

Sunday, May 9, 2010

E12 resistor chart

here is my E12 resistor chart


Parallel Circuit

This is a parallel circuit, the current has 2 or more paths to follow so this allows the circuit to work even after the loss of one or more components. the equation for working out the values in slightly more complex than for the series circuit because the resistance values have to be added as fractions. the voltage is the same across all branches and the total current is the sum of the branch currents.