Chapter 2 Flashcards
Conductors
3 or fewer electrons
insulator
5 or more electrons
semiconductor
four electrons
voltage
- defined as electrical pressure
- force that causes the movement of electrons in the conductor
ammeter
the instrument used to measure electrical current flow in a circuit
ohmmeter
an instrument used to measure the resistance to electrical flow
voltmeter
used to measure the voltage or electrical pressure through a circuit
jumper wires
connecting one end of the jumper wire to battery positive will give an excellent 12 volt power supply
-Can also be used to bypass individual wires connectors components or switches
test lights
- used when the technician needs to look for electrical power in the circuit
- limited because it does not display voltage though
- do not use to test computer control modules it may damage them
Logic probes
used to test computer modules
Current
defined as the rate of electron flow
Parallel Circuit
1) voltage applied to each parallel leg is the same
2) Voltage drop across each leg will be the same unless one leg has different resistances
3) total resistance of the parallel will always be less than its lowest resistance
4) current flow through the legs will be different if the resistances are different
5) The sum of the current in each leg EQUALS the total current of the parallel circuit
series circuit
1) total resistance is the sum of the resistance
2) current is the same at all points of the circuit
3) voltage drop across each resistance will be equal if the resistance values are the same
4) the voltage drop across each resistance will be different if the resistances are different
5) sum of all voltage drops equals source voltage (total voltage)
Series-Parallel Circuit
1) total resistance is the sum of the parallel circuit AND the series together (R1xR2/ R1+R2 AND series)
2) voltage drop over the parallel branch is determined by the resistance value of the series resistor
3) total amperage is the sum of the current flow through each parallel branch
4) amperage through each parallel branch id determined by the resistance in the branch
Ohms law
it takes 1a to push 1 volt through one ohm of resistance
Kirchoff’s law
1) algebraic sum of the currents entering and leaving a point must be zero
2) the algebraic sum of the voltage sources and voltage drop in a closed circuit must equal zero