Fundamentals of Transfomers

Fundamentals of Transformers

1. High voltage causes shocks
2. High current causes wires to heat up.
3. Power-->Voltage x Current

P=VI

To transfer power efficiently, we need to transform it using-->

STEP-UP

TRANSFORMERS and

Step-Down

These change voltage to an appropiate amount for the use of electricity at that moment.

In power stations and power lines we need to consider point "2."above.

• Heating wastes energy.
• So we use high voltages and low currents. But in our homes we need to consider point "1."
• We don't want to get shocked.
• So we use low voltages and high currents.

In each case, POWER is transfered at the same level.

We get the same power from:

1A at 240V

As we do from:

240V at 1V

Homework reminders

Homework set today was:

7A and 7J - Not really homework because it counts towards your experimental mark at the end of the year so it must be completed. Write up the egg-speriment, complete with observations, explanation, and conclusion. A reminder of what these are all about are in Pablo's post below. This is to be written up to hand in for the lesson next week same time (Tuesday's lesson). NO Web team exemption, everyone must write up experiments in their books.

8P - One element from the periodic table, but NOT the same one as someone else. Make a poster A4 size to form a LARGE periodic table on my ceiling. Check Hugo's post below to make sure that you and other people are not doing the same element. Web team you may do yours on the web but that won't help to decorate my ceiling will it...

8C - P65, Q1-4 for collection on Friday to be marked over the weekend. There goes my chances of having any fun this weekend. Web team exemption if work posted of a similar nature on the web by Friday.

9S - Finish off funky pH scale for next lesson, web team exemption if work posted on the web before friday, including Ana and the photography team.

9P - P65, Q1-4, collection Friday. Web team exemption if similar posted on the web by friday

Y10 - For failing to attain all the objectives in yesterdays lesson you will be set additional homework in tomorrow's lesson

Y11 - Finish up those calculations for tomorrow, where I will try to melt a piece of wire using a slinky spring and a power pack. Calculations important and therefore no web team exemption.

No excuses guys and girls you've been reminded.