The Glossary |
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Note: If you know a term that should be added on this page, type up the correct definition and email it to me. I welcome your suggestions. | |
Term |
Definition |
Frequently Asked Questions | Check here for some great reading! This section will grow throughout the year. So keep checking back. |
Amperage |
Not a correct term, see current. |
Ampere or Amp |
The Ampere, or Amp (A) for short, is the unit of current flow. We measure current by the Amp. 1 ampere is 1 coulomb (C) of electrons moving past a point in a circuit every second. If two coulombs of electrons move past a point in a circuit every second, the current in the circuit would be 2 amperes or 2A. |
Capacitor |
A device that stores charge. Think of a capacitor as acting like a bucket that can not be overfilled. Capacitors can be charged up and then discharged. Just like a bucket can be filled up and later emptied out. |
CDS |
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Charge |
A group of electrons all gathered up somewhere. The more the electrons, the bigger the negative charge. We measure charge by the Coulomb. 1C = 6.25 X 1018 electrons for a negative charge or the same amount of protons for a positive charge. |
Conductor |
A material that allows current to flow through it. All metals are good conductors. Touching a bare conductor that is connected to a voltage source can be very dangerous and could cause electrocution. Never touch a conductor that is connected to a voltage source larger than 12V. It could be dangerous! |
Current |
Current is the flow of electrons. Electrons have a negative charge and move from the negative side of a voltage source out through a circuit and back to the positive side of the voltage source. Current can not flow in a circuit unless there is a complete (unbroken) path for them to move through. Current is measured in Amperes or Amps for short. Current |
Diode |
A device that lets current pass in only one direction. Transistors have two very specially designed diodes inside them. |
EMF |
EMF stands for Electromotive Force which is a voltage. A battery voltage can be referred to as an EMF. Typically this term is related to the voltage generated in a wire when the wire is cut by a magnetic flux line. A back voltage, or Back EMF is generated inside a rotating motor which reduces its current when the motor is running fast. |
Frequency | Frequency, as it relates to AC voltages, is how many pulses or cycles in one second's time. If you listen closely to a battery operated clock with a second hand, you will hear one tick every second. One tick every second is also called one cycle per second or one Hertz. Named after a scientist, the Hertz is the unit of frequency. Two ticks every second would be two Hertz and so forth. When a telephone rings, the frequency is 20 Hz. or twenty Hertz. The higher the frequency the higher the pitch of the sound. |
Inversely Proportional | Take
a look at the Ohm's Law formula. R stands for resistance, V stands for voltage, and I stands for current. Since the R is below the line, an increase in resistance causes the current to be lower. In fact, if the resistance is doubled in a circuit, the current will cut in half. Because of this relationship we say that the current in a circuit (I) is inversely proportional to resistance (R). As R increases, I will decrease. See also: Proportional and Ohm's Law Audio Experiment: Get a pencil and paper and click here. 500Kb |
MagnemotiveForce (MMF) |
MMF stands for Magnemotive Force.This term deals with electromagnets.MMF = A x T or amps times the number of turns in the coil of wire. MMF is the potential to produce magnetic flux. (((Covered in depth Edison Project 7))) |
Ohm's Law |
Ohm's Law describes the relationship between Voltage, Current and Resistance. Ohm's Law is expressed here as a formula. I, stands for current, V stands for voltage and R stands for resistance.See also: proportional and inversely proportional |
Oscillator | An oscillator is a circuit that takes a DC voltage and converts it to an AC voltage or at least a pulsating output. Where DC is a steady voltage an AC voltage is not steady at all. It changes! |
Proportional |
Look
at the Ohm's law formula. You will notice that the V is on top in this formula. If the V (voltage) is increased, the current in the circuit will also increase. If the voltage doubles in a circuit, the current will also double. This relationship is called directly proportional or just proportional for short. See also: Inversely Proportional and Ohm's Law Audio Experiment: Get a pencil and paper and click here. 400Kb |
Reciprocal |
The reciprocal of a number is found by dividing 1 (one) by the number you wish to find the reciprocal of.Example: The reciprocal
of 4 is 1/4.
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Resistance |
Opposition to current flow. Resistance holds back on current and decreases the amount of current flow. You can think of a resistor as a pinch in a water hose. The pinch restricts the current flow of water just like a resistor restricts the flow of electrons in a circuit. More resistance means less current can flow. Resistance |
Resistance | The opposition to current flow. Resistance limits current to a safe level in a circuit. |
Resistor |
A device that holds back the flow of current. |
Series Circuit |
A series circuit is a circuit that has only one path for current to flow. |
Series String |
A series string is a small part of a big complex circuit that is like a series circuit. Two or more components in a circuit that share the same exact current flow are in a series string with each other. If you remove one of the components in a series string the devices in that series string will not have any current flow through them either. |
Transistor |
A three terminal device that can be used to amplify small signals and make them louder. Transistors are also used as switches to turn things on or off. |
Voltage |
The push or pull that causes current to flow. More voltage means more current. Voltage |
Watt | We measure electric power by the Watt. |
The glossary is a great idea suggested and co-authored by Joseph O'Connell. |