Electrical Circuit Diagrams

Transcription

1 Electrical Circuit Diagrams

2 What is an Ammeter? A device used to measure electrical current (Rate of electron flow) measured in Amps

3 What is an Voltmeter? A device used to measure potential difference. Measured in voltage.

4 Electrical Circuits Symbols are used to represent different parts of a circuit. This makes drawing circuit diagrams much easier. conducting wire V lamp A voltmeter ammeter battery switch resistor Circuit Diagram Symbols

5 Electrical Circuits Symbols are used to represent different parts of a circuit. This makes drawing circuit diagrams much easier. V

6 Electrical Circuits There are 2 basic types of circuits: Series Circuits Parallel Circuits There is a single path for electrons. There are multiple paths for electrons.

7 Series Circuits A series circuit has only one path for current to flow. Since all of the electrons must travel at the same speed around the circuit, the current passing through any all points point in in aa series series circuit circuit is is the the same. same. Current I1 Is + One path means that the current is the same at all parts of the circuit. I3 Is = I1 = I2 = I3 I2

8 Series Circuits The electrons must go through all of the lamps in the circuit, so the voltage is shared between each of the lamps. If there were fewer lamps, each lamp would be brighter, because each would get more voltage from the battery. Voltage V1 Vs One path means that the current is the same at all parts of the circuit. V3 Is = I1 = I2 = I3 V s = V1 + V2 + V3 V2

9 Series Circuits The electrons must go through all of the lamps in the circuit, so the voltage is shared between each of the lamps. If there were fewer lamps, each lamp would be brighter, because each would get more voltage from the battery. Voltage V1 Is = I1 = I2 = I3 V s = V1 + V2 Vs Fewer lamps means more voltage for each. V2

10 Series Circuits The electrons must go through all of the lamps in the circuit, so the voltage is shared between each of the lamps. If there were fewer lamps, each lamp would be brighter, because each would get more voltage from the battery. Voltage V1 Is = I1 = I2 = I3 V s = V1 Vs Fewer lamps means more voltage for each.

11 Series Circuits The electrons must go through all of the lamps in the circuit, so the voltage is shared between each of the lamps. If there were fewer lamps, each lamp would be brighter, because each would get more voltage from the battery. Voltage V1 Is = I1 = I2 = I3 V s = V1 + V2 + V3 Vs V2 V3

12 Series Circuits Each lamp resists the movement of electrons. Since electrons have to pass through all of the lamps, the overall resistance of the circuit (Req) is the sum of the resistance from all lamps. Resistance R1 Is = I1 = I2 = I3 V s = V1 + V2 + V3 Req One path means that electrons are resisted by each lamp. R3 Req = R1 + R2 + R3 R2

13 Parallel Circuits A parallel circuit has more than one path for current to flow. Since the paths are independent of each other, the current in each path may be different. Current at the source (Is) is the sum of the current at each lamp. Current Is = I1 + I2 + I3 Is + I1 I2 I3 Some paths may allow electrons to flow more freely than others.

14 Parallel Circuits Electrons only have to go through one lamp to get back to the battery. So each lamp gets the full voltage of the battery. Having fewer lamps in the the circuit circuit would wouldhave haveno noeffect effectonontheir their brightness,, brightness.but But theit battery would drain the would lastbattery longer.faster. Voltage Is = I1 + I2 + I3 V s = V1 = V2 = V3 Vs V1 V2 V3 Many path means that all of the lamps get the battery s full voltage.

15 Parallel Circuits Electrons only have to go through one lamp to get back to the battery. So each lamp gets the full voltage of the battery. Having fewer lamps in the the circuit circuit would wouldhave haveno noeffect effectonontheir their brightness,, brightness.but But theit battery would drain the would lastbattery longer.faster. Voltage Is = I1 + I2 + I3 V s = V1 = V2 Vs V1 V2

16 Parallel Circuits Electrons only have to go through one lamp to get back to the battery. So each lamp gets the full voltage of the battery. Having fewer lamps in the the circuit circuit would wouldhave haveno no noeffect effect effecton on ontheir their their brightness,, brightness. brightness.but But theit battery would drain the would lastbattery longer.faster. Voltage Is = I1 + I2 + I3 V s = V1 Vs V1

17 Parallel Circuits Resistance In a parallel circuit, the overall resistance (Req) of the circuit is actually smaller than the smallest resistance in the circuit. The calculation of Req is a little complicated. Is = I1 + I2 + I3 V s = V1 = V2 = V3 Req R1 R2 R3 Current can flow through any path. The more paths available to lower the total resistance.

18 Page: 553 Sample Problem #1: Draw a circuit diagram showing an electric cell, a switch and three lamps connected in series.

19 Step 1

20 Step 2

21 Step 3

22 Sample Problem #2: Draw a circuit diagram showing a two cell battery with three lamps connected in parallel. Place a switch for controlling each lamp.

23 Step 1

24 Step 2

25 Step 3