Cheatography

# Electric Circuits Cheat Sheet by Coalmine

WJEC Physics Triple, unit 1.1, electric circuits Symbols, Current and Voltage, Resistance, Series and Parallel, Equations, I-V Graphs, Graphs

### Symbols To Know

 Switch Thermistor Fuse Light Dependent Resistor (LDR) Lamp Variable Resist­or/­Reostat Light Emitting Diode (LED) Diode Resistor Voltmeter Battery Ammeter A.C Power Supply D.C Power supply Battery Pack Speaker

### Series and Parallel Circuits

 Series Parallel Current flowing in each component is the same Current is shared at each junction Useful when you need a warning when something breaks Useful when you want other components to work when another is broken. All components receive the same voltage

### I-V Graphs The graphs can also be reversed (V-I Graphs)

### Current And Voltage

 Voltage Current PUSH behind current Rate of flow of electrons Measured in Volts (V) Measured in Amps (A) Measured by voltmeter, which is placed in parallel to circuit Measured by ammeter, which is placed in series to circuit The more batteries, the more voltage The more resist­ance, the less current
NOTE: Only ENERGY is used up

### Resistor

 Resistors are the opposition to flow of current.

### Resistors continued

 It is measured in Ohms' and is calculated by Ohm's Law
NOTE: A filament lamp is also a resistor

### Equations

 Voltage = Current x Resistance V=IR Power = Current x Voltage P=IV Power = Current2 x Resistance P=I2R Total Resistance in Series R1 + R2 + R3 ... Total Resistance in Parallel 1/R1 + 1/R2 + 1/R3 ...

### Thermi­stors and LDR Graph ### Other things

 Thin wire - Less current Thick wire - More current Long Wire - Less current Short Wore - More current Mains voltage is usually 230V