Circuits

 Has only one path for electrons to move through.  Current is the same at every point in the circuit  I f = I R1 = I R2  When we add a lamp in series, the resistance goes up. seriesresistance seriesresistance  current reduces - lamps are dimmer. reduces

Parallel Circuits  More than one path  Current adds up when another “branch” is closed  I f = I R1 + I R2 + I R3  Battery Runs out faster

Parallel  Most household circuits are parallel  When we connect one lamp to the battery it takes a current of 0.4 amps from the battery. from the batteryfrom the battery  When we connect the second lamp in parallel, it comes on with the same brightness. So it is also taking a current of 0.4 amps. parallel current of 0.4 amps parallel current of 0.4 amps  the current being taken from the battery is 0.8 amps from the batteryfrom the battery  the two currents flow parallel to one another.

Energy In Your Home  How does the power company know how much energy you use?  How can you conserve energy and reduce the cost?  What potential Hazards Exist in yourt house?

Paying The Big Bucks  We pay 9.22 cents for every Kilowatt hour we use  A Kilowatt is 1000 watts  A kilowatt hour is the number of kilowatts used in one hour

Reading the meter  A The pointer on the far right is directly on number 5. Read as 5.  B The second pointer from the right has just passed 9, and is between 9 and 0. Read as 9.  C The next dial has passed 8, and is between 8 and 9. Again, read the smaller number which the pointer has just passed, which is 8.  D The pointer on the next dial looks like it is right on the 4. But, the dial to its right has not passed zero. So, you would read this dial as 3.  E The pointer on the far left dial has passed 8, and is between 8 and 9. Read the smaller number which the pointer just passed, which is 8.  This meter reads 83,895 kWh

How much…..?  Last month our meter read 83,895 kWh  This month it reads 85,522 kWh  How many kWh did we use? How much did it cost?  85,522 kWh - 83,895 kWh = 1627 kWh  1627 kWh x $ = $150.01

Conserving Energy  Let’s look at two kinds of light bullbs Incandescent light bulbs use about 10% of the available current to burn the light and the rest is given off as heat! If every household in North America. replaced one light bulb with a compact fluorescent light bulb (CFL), it would prevent enough pollution to equal removing 1.5 million cars from the road.

The Difference - Technology The key difference between Fluorescents and Incandescents Is how they "create" light. Fluorescent bulbs outlast up to 13 incandescent or halogen bulbs. The Difference - Cost Check the Facts! A compact fluorescent may cost more to purchase than an incandescent, but that's where the story ends. Compacts can typically save 8 to 12 times their cost Temperature 90% of the energy consumed by an incandescent bulb is wasted heat. This makes the bulb extremely hot to touch and very unsafe.

Typical costs  Device Typical consumptionCost per hour  Air Conditioner 15,000 watts$1.50  Water heater 4,000 watts40 cents  Water pump3,000 watts30 cents  Space heater1,500 watts15 cents  Hair drier1,200 watts12 cents  Electric range 1,000 watts10 cents  Refrigerator1,000 watts10 cents  Computer 400 watts4 cents  Light bulb60 watts0.6 cents

SAVINGS  How about just turning one light off?  100 watt bulb uses.1 kW/h  At $ per kWh that’s $0.92 per 100 hours  If we leave our lights 5 hours each night that 100 hours will last for 20 days  Over 1 month (30 days) we spend around $1 per light bulb - an average house spends $15 per month on lights.