Potential Difference, Current and Resistance Voltage Current Resistance How to Measure Voltage, Current and Resistance

Potential Difference Voltage (V) = The source of energy in a circuit provides energy to the electrons. It is how much energy that the electrons pick up from the source. igher the potential difference (voltage) the greater the potential energy of each electron PD – another words = voltage A battery had potential energy in the electrolyte of its electrochemical cells The chemical in the electrolyte react with the electrode that causes a difference in the amount of electrons between the two terminals One end has a negative charge (electrons) and the other end had the positive charge The ngative electrons are attrached to the positive end of the battery and move toward it throught the use of a conductor (ie copper wire) like falling apple from a tree PD – causes current to flow in a closed circuit

Measuring Voltage Volt (V) – is the unit used to measure potential difference Voltmeter- is connected in parallel What is the apparatus used to measure potential difference? Placing the two end of the voltmeter and measure the potential differnece in a battery

Current Current (I) = is the how fast electrons are moving through the circuit. Think of the continuous flow of electric current like water flowing in a stream The water keeps flowing unless the source dries up As long as the battery continues to separate charges on its terminals (ends) the electrons will continue to flow WB – example of DC WB – example of alternating current

Measuring Current The electric current is measured in units called – Ampere (A) Ammeter- measures current in a circuit. An ammeter is connected is series. Current Energy moving past a point in the circuit every second

Resistance ALL SUBSTANCES RESIST ELECTRON FLOW Resistance (R)- to slow the movement of electrons in a circuit ALL SUBSTANCES RESIST ELECTRON FLOW Conductors have low resistance values Insulators have high resistance values When a substance resists the flow of electrons, it slows down the current and converts the electrical energy into other forms of energy The more resistance a substance has they more energy is gains from electrons that pass through it The energy gains by the substance is radiated to its surroundings as heat and/or light energy The more resistance a component has the smaller the conductivity

Measuring Resistance Ohm (Ω) – the unit used to measure resistance Ohmmeter Measures electrical resistance Multimeter = measures differnece, current, or resistance Ohm – greek leter omega