Direct Current ( DC ) Electrical Systems Flashcards
What are the rules for a series and parallel circuit?
In a series circuit, the voltage across the circuit is the sum of the voltages across each component. The current ( amperage ) is the same through each component.
In a parallel circuit, the voltage across each of the components is the same. The total current ( amperage ) is the sum of the currents through each component.
What is Ohm’s Law?
V=AxR
Volts= Amperage x Resistance
What is Watt’s law?
W=VxA
Watts= Volts x Amperage
LED
Coil
Flasher
Bulb
Resistor
Battery
What are the 6 sources of Voltage?
• Light= The process through which a solar cell converts sunlight into electricity
• Pressure ( Piezoelectricity ) = Produced from crystalline materials, (eg: propane cook top ignitor)
• Induction = Relationship between electricity & magnetism
•Heat = Causes electrons to flow in a conductor (eg: Burning wood, the sun)
•Chemical = Action on cell plates that maintains electron flow (eg: batteries )
•Friction = Rubbing two materials together ( eg: Static shock, Match book)
Code 5.12.11 Overcurrent Protection
•5 Amp - 18 AWG
•10 Amp - 16 AWG
•15 Amp - 14 AWG
•20 Amp - 12 AWG
•30 Amp - 10 AWG
•40 Amp - 8 AWG
•50 Amp - 6 AWG
What is a Schematic Diagram?
( Ladder Diagram )
•Ladder diagram is the simplest form of schematic diagram
•Shows circuit components on horizontal or vertical lines regardless of location
•Ladder diagrams are used for troubleshooting
•Can be drawn from top, bottom, left to right, or vise versa.
What are electrical diagrams?
Electrical diagrams are a common method of depicting electrical circuits.
There are 4 types of diagrams:
• Schematic
•Wiring diagrams
•Block diagrams
• Pictorial Diagrams
USB Charger
•Charging stations provide 5.0 VoltDC
•Used to power or charge electronic devices
•Test using a voltmeter or a USB tester
Ohm ( R )
Base unit for the measurement of resistance or opposition to electron flow.
Watt ( W )
Base unit for the measurement of electrical power consumption.
1 Watt = 1 Volt x 1 Ampere
Ohm’s Law
It takes one volt of potential to move one ampere of current through one ohm of resistance.
Voltage drop in a series circuit will…
Always add up to the total volts
What is voltage drop ( VD )
Voltage is used up when current flows through a resistance.
Relays
Low amperage control circuit controls a higher amperage load circuit
Frequency
Hertz = HTz
Resistance
Ohm’s = R
Electrical power
Watt’s = W or P
Intensity of flow
Amp = A or I
Electromotive Force
Volts = V or E
Wiring Diagram
•Emphasizes connection between elements of a circuit or system
•Use horizontal and vertical lines to represent the wires
•Uses simplified pictorials that clearly resemble circuit / system components
•Equipment and wiring are placed on the drawing to approximate the actual physical location in a real circuit
DC Electrical Systems
Direct current is an electric current that is unidirectional, so the flow of charge is always in the same direction.
The direction and amperage of DC does not change
It is used in many household electronics and in all devices that use batteries.
⚡️ DC Electrical Theory
In DC circuit theory, electrical current is the movement or flow of electrical charge and is measured in amperes for intensity.
It is the continuous and uniform flow of electrons ( negative particles ) around a circuit that are being pushed by the voltage ⚡️ source
Crystalline
Orderly arrangements of atoms
Current
Current is the rate at which electrons flow past a point in a complete electrical circuit
What are 3 common resistors?
•Fixed
•Stepped
•Variable
Resistors are used in circuits where full current flow may not be required.
A side effect is that they produce heat
Circuit protection devices
• Fuses
• Fusible links
• Circuit breakers
• Thermal limiters
Block diagram
• Use blocks & arrows to represent the relationship between components.
• Simplest form of electrical diagrams
•Typically used at the initial stage of developing the electrical drawings
• Lack detailed information about the layout & connections in a circuit
Pictorial Diagram
•Shows the circuit in detail ( as they really look )
•Indicates how the wiring is attached
•Pictorial diagram can be used to locate components in a complex system
Applied Voltage
•Voltage avaliable to an individual branch circuit
Electrical Pressure
•High concentration of electrons at one location as compared to another potential difference
What are the three main parts of an atom?
•Protons
•Neutrons
•Electrons
What is a semiconductor?
•4 electrons in outer valance
•Has some characteristics of both insulators & conductors
What is an Insulator?
•5-8 electrons
•Outer valance ring bond to electrons is very strong
Current or Conventional theory
Used in the RV industry
Positive to negative
( + ) ( - )
Conductors
•When an atom has between 1-3 electrons in its outer valance ring
Electron Theory
Used for electronics
Negative to positive
What is Hertz?
Speed of frequency of voltage per second
AC sign wave moves at 60 Htz per second
Non-Crystalline
Random pattern of atoms
Source Voltage
Avaliable voltage
Ampere ( I )
Base unit for the measurement of electron flow
⚡️ Volt
Base unit for the measurement of electrical pressure or “Push”
