Electric current is measured in units called Amp\u00e8res A or Amps for short In our

# Electric current is measured in units called ampères

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Electric current is measured in units called Ampères (A), or Amps for short. In our work in electronics we will usually be dealing with much smaller units of current such as mA 3 1 A or 10 A 1000 and μA 6 1 A or 10 A 1000000 æ æ æ æ æ æ The electric current is not used up by the components in a circuit but it transfers energy from the voltage source to the various components making up the circuit. Electric current is measured using an ammeter . The ammeter is placed in series within the circuit, as shown in the circuit diagram on the right. 4 A Current flow A Electron flow 12 V 0 V A +
Topic 2.1 – Current, voltage, resistance and power. Voltage. Voltage is supplied by a battery, cell or power supply and is measured in volts ( V ). The voltage of a power supply is the driving force that pushes the current through the components of a circuit. The larger the voltage the bigger the push on the current. The voltage across a circuit component, e.g. a bulb converting electrical energy into heat and light is sometimes called a potential difference (p.d.). Potential difference is also measured in volts ( V ) . Potential difference is measured using a voltmeter . The voltmeter is placed in parallel to the component as shown in the diagram opposite. From this point on we will simply refer to potential difference simply as voltage. 5 12 V 0 V V
Module ET2Electronic Circuits and Components.Resistance.Resistance is the property of a material which restrictsthe flow of electricity. Energy is converted into other forms (e.g. light, heat), as the voltage across the component drives the current through it. The unit of resistance is the Ohm (Ω). In electronics we usually dealwith much larger units of resistance askΩ (1000Ω or 103Ω), and (1000000Ω or 106Ω)What causes resistance? . What factors affect resistance? R 6
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