* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Circuits
Switched-mode power supply wikipedia , lookup
Ground (electricity) wikipedia , lookup
Thermal runaway wikipedia , lookup
Electrical substation wikipedia , lookup
Electrical ballast wikipedia , lookup
Electric machine wikipedia , lookup
History of electromagnetic theory wikipedia , lookup
Mercury-arc valve wikipedia , lookup
Power engineering wikipedia , lookup
Buck converter wikipedia , lookup
Skin effect wikipedia , lookup
History of electric power transmission wikipedia , lookup
Stray voltage wikipedia , lookup
Surge protector wikipedia , lookup
Mains electricity wikipedia , lookup
Opto-isolator wikipedia , lookup
Current source wikipedia , lookup
Circuit breaker wikipedia , lookup
Resistive opto-isolator wikipedia , lookup
Rectiverter wikipedia , lookup
Earthing system wikipedia , lookup
Circuits QOD: When building a circuit with the least resistance, what type of wires would be used? Electric Current • is the flow of electric charge • In solids such as copper wire, electrons are free to flow through the substance but protons can’t • In fluids such as a car battery, both positive and negative ions are free to flow • Current is measured in amperes(A) – 1 amp is the flow of 1 C of charge per second or 6.24 billion electrons per second Voltage • is potential difference, which you get when you connect a positive terminal to a negative terminal and form a circuit • Measured in Volts(V) • Charges will not flow without this potential difference, which provides the “electric pressure” to move the electric field Electric Resistance • the resistance to current(flow of electric field energy) by the conducting material itself & is measured in ohms (Ω) • More resistance = less flow of electrons Affecting Electrical Resistance • • • • Depends on the conductivity of the wire, Thickness -thick wires have less resistance Length – long wires have more resistance Temperature - higher temp means more resistance • Superconductors – no resistance to current at low temperatures Ohm’s Law • current = voltage/resistance or I = V/R • states that the current through a conductor between two points is directly proportional to the potential difference across the two points. • I = current measured in amperes • V = voltage measured in volts • R = resistance measured in ohms 1. While cooking dinner, Mariah’s oven uses a 220.V line and draws 8.00 A of current when heated to its maximum temperature. What is the resistance of the oven when it is fully heated? 2. What is the resistance of the heating element in a car lock de-icer that contains a 1.5-V battery supplying a current of 0.5 A to the circuit? Ohm’s Law and it’s Effect on You • Normally, the human body has a resistance of about 100,000 Ω, but if you are soaked with saltwater, it can be lowered to just 100 Ω, increasing current dramatically • Current in Amps Effect 0.001 Can be felt 0.005 Painful 0.010 Involuntary Muscle Spasms 0.015 Loss of muscle control 0.070 Fatal if it lasts for more than 1s DC vs AC • Electric current may be AC or DC • DC – Direct Current – flow of charge is always in one direction, such as a battery(- to +) • AC – Alternating Current – Electrons in the circuit move first in 1 direction and then the opposite direction. – Here in the US, AC circuits alternate back & forth at 60 Hz or 60 times per second and outlets are at 120V Electric Power • the rate at which electrical energy is converted into another form such as mechanical energy, heat, or light • P=IXV • Power is measured in Watts(W) • I = current measured in amps • V = volts 3. The lighter in Jordan's car has a resistance of 4.0 Ω. a) How much current does the lighter draw when it is run off the car's 12- V battery? b) How much power does the lighter use? 4. A 120.-V outlet in Ashtin's college dorm room is wired with a circuit breaker on a 5-A line so that students cannot overload the circuit, a) If Ashtin tries to iron a blouse for class with her 700-W iron, will she trip the circuit breaker? b) What is the resistance of the iron? Circuits • 2 types: – Series – A circuit which has only one pathway for the electrons to flow between the terminals of the power source – Parallel – A circuit which has multiple separate paths that the electrons can take Series Circuit • Only 1 pathway • Current is the same throughout the circuit • Total Resistance is the sum of all resistances – The same applies to current and voltage • If one bulb burns out, they all go out because the circuit is broken Parallel Circuit • • • • Multiple pathways for current One bulb goes out, the others stay lit Voltage is the same across each bulb Total resistance decreases as more branches are added Circuit Schematics • Circuits are described using simple diagrams called schematic diagrams