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.

Series circuit

This is a Series circuit, the current has only one path to follow, if any of the components are removed then the current will cease to flow. the total resistance can be easily calculated by adding the individual component resistance. from there its simple ohms law for the rest of the values.

Sunday, May 2, 2010

Resistor color code chart

we have recently been exploring the colored band on resistors, the chart above is an invaluable tool in being able to read and comprehend resistors.the resistor above the chart has a value of 22 ohms with a tolerance of 5%. 

Sunday, April 18, 2010

first week back and the topic is computer ergonomics.

Some factors that influence computer ergonomics are, back position, how high your monitor is set in relation to your eye level, what angle you set your keyboard at and even the angle of your knee (?????).