A potentiometer is a three terminal resistor with a sliding contact. A rheostat is a two terminal variable resistor. A variable resistor is any resistor that allows you to change the amount of resistance. Potentiometers and rheostats are both types of variable resistors.
Current is measured in amps. The formula to use here is: I = V/R I = 8/4 I = 2
A voltmeter is used to measure the potential difference between two points. It is used in parallel with a circuit when measuring voltage. Ideally a voltmeter should have high resistance so that no current flows through it while measuring the potential difference between the two points.
The band code for a resistor is as follows: ‣ Black is 0 ‣ Brown is 1 ‣ Red is 2 ‣ Orange is 3 ‣ Yellow is 4 ‣ Green is 5 ‣ Blue is 6 ‣ Violet is 7 ‣ Gray is 8 ‣ White is 9
A milliamp is one thousandth of an amp. So every amp equals 1,000 milliamps: 3 x 1,000 = 3,000.
Frequencies are measured in kilohertz, megahertz, or gigahertz. AM radio stations broadcast in the 530-1,700 kHz range.
Pushing the button breaks the circuit. When you release the button it returns to its normally closed (on) position.
The most conductive material is Silver followed by Copper and Gold.
Capacitors consist of one or more pairs of metal conducting plates that are separated by an insulator. The insulator is called the dielectric. An electric charge builds up when a voltage is applied across the plates, which creates an electric field.
The hertz, or Hz, is the SI unit of cycles per second and is a measurement of frequency. The Ohm is a measurement of resistance and the Ampere is a measurement of flow rate of electric charge.
A kilowatt-hour (kWh) is a unit of energy equivalent to one kilowatt (1 kW) of power expended for one hour
P represents power, which is measured in watts. I represents current, which is measured in amperes. V represents voltage which is measured in volts.
In a basic circuit model, there is a voltage source (pictured here as a battery at points A and B), a load, and conductors. The conductors are drawn using the lines and arrows. The load in this model is the light bulb pictured at point C. Examples of loads are light bulbs, resistors and motors.
The formula to use here is: V = I x R V = 10 x 6 V = 60
Electrical resistance is measured in ohms, and can be measured with an ohmmeter.
An electrical cell supplies electrical current. Examples include batteries and solar cells.
Normally, the system voltage is around 14.5 volts. Car accessories increase the demand on the system (dropping the voltage) but this is compensated by the voltage regulator, which increases the alternator's output until the system voltage is back to approximately 15.
A series-parallel circuit has some loads wired in series and some loads wired in parallel. The loads in this circuit are R1, R2, and R3. R1 is wired in series while R2 and R3 are wired in parallel.
