Current, Resistance, and Simple Circuits
A capacitor is a device used to store electrical energy. There are two different ways to arrange circuit components: Series Current is constant, voltage varies Parallel Current varies, voltage is constant Review
Current – The flow of electric charges through a piece of material. Throughout these notes, we are going to compare circuits to water. Current is like the speed that water is flowing. Rapids would represent a large current. Current is the rate at which charges flow through a specific area. Current
# of Charges Duration (Time)
Resistance – A charged particle’s resistance to a change in motion in response to an external force. Resistance is like the widening or shrinking of a pipe to change the rate of flow of water through a pipe. Resistors are used to control the current in different parts of a circuit. Resistance
Current, Resistance, and Voltage all affect each other. Voltage is the push. Current is the flow. Resistance is the slowing down of current. Ohm's Law Demo Ohm's Law Demo Ohm’s Law
Voltage Current Resistance
Resistivity Length of Material Cross-Sectional Area Temperature Temperature Coefficient of Resistivity
Electrical Power
Direct Current Circuit (DC) – A circuit that has a current that is constant in magnitude and direction. Alternating Current Circuit (AC) – A circuit that has current that is changing in magnitude and direction. Electromotive Force – The maximum possible voltage that a battery can provide (Symbol: ε) Direct vs. Alternating Current
Remember the symbols from last week: Wire Battery Capacitor Switch And two new ones: Resistor Light Bulb Circuit Design
Resistors in Series R1R1 R2R2 R3R3 Battery
Resistors in Parallel R1R1 R2R2 R3R3 Battery
Let’s take a look at why Current and Voltage change depending on the type of circuit we have. Circuit Construction Circuit Construction
Calculate the current and voltage delivered to each resistor in the circuit shown below. Practice Problem 18 Volts 4 Ohms 2 Ohms 3 Ohms 1 Ohm