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Electricity
2
Question | Answer |
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Inductive Reactance | An opposition to the change of current on an inductive element. It is proportional to the sinusoidal signal frequency and the inductance. Lowers total voltage. |
Capacitor (Condenser) | A passive two-terminal electrical component used to store energy in an electric field. Contain at least 2 electrical conductors separated by a dielectric (insulator). |
Semiconductor | Has electrical conductivity b/t that of a conductor and an insulator. Differ from metals by decreasing electrical resistivity. Can also display properties of passing current more easily in one direction than the other. |
Doping (Semiconductor) | In semiconductor production, this intentionally introduces impurities into an extremely pure (also referred to as intrinsic) semiconductor for the purpose of modulating its electrical properties. |
Diode | Placing a piece of N- Material (Negative special material) in contact with P- Material (Positive) makes this junction device. |
Transistors | A semiconductive device capable of more complex functions than a diode, including amplification, nesting 2 pieces of N- Material on each side of a P- Material (NPN). |
Transistor Amplifiers | Has high impeadence and is suitable for use in input circuits in EEG amplifiers. |
If there is a surplus of electrons, what type of semiconductor is this? | N-Type. |
If there are more protons than neutrons, what type of semiconductor is this? | P-Type. |
What is barrier voltage? | Poles in the P-Type material travel to the N-Type until there is an imbalance in charge great enough to prevent the migration from continuing. |
What is a forward biased junction diode? | When migration is occurring and is conducting current, it is this. |
What is a junction diode that has no current? | Reverse Biased. |
Is a forward biased junction diode a conductor or an insulator? | Conductor. |
What is a circuit that has an output voltage only during alternating 1/2 cycles? | A half wave rectifier. |
What are the 3 sections of an NPN transistor? | 1 piece of P material between 2 slices of N material. 1. N = Emitter. 2. P = Base. 3. N = Collection. |
What type of current flow do you have with a NPNP transistor? | From base to remitter, Conventional current from + to -. |
What type of current flow do you get with a PNP transistor? | Elector current from emitter to base (opposite) and said to be biased. Electron Flow. |
What does it mean when a transistor is biased? | Voltages of proper polarity must be applied to insure normal operation. |
A Transistor Amplifier has... | High input impedance. |
What happens when voltage is applied to the gate of a transistor amplifier? | It creates an electrostatic charge and a FIELD develops. |
What does the Insulated Gate do? | It gives an even higher impedance in a transistor amplifier and acts as a variable resistor. |
Where is zero in a Galvanometer? | Center position. |
What converts electrical energy to mechanical movement? | A Galvanometer. Electrical Mechanical Transducer. |
What is an ink-Writing Galvanometer? | Precisely designed coils, magnets, etc. |
What is an integrated circuit? | Several transistors, diodes, capacitators, and resistors packed into a small, structured unit, which may be only a few millimeters square (often a microchip). |
What is another name for integrated circuit? | Chip / Microchip. |
Transformers | Devices that transfer electrical energy from one circuit to another. They are used to “step up” or “step down” the voltage. |
Ground | 3 Types: 1: Earth (not all the same). 2. The chassis or case-ground (in casing). 3. Common connection of electronic circuitry (circuit ground). |
Impedance | The combined effects of resistance and reactance (of the wires on the head). |
Common Mode Signal | Rejects external interference from radiating electrical fields, such as 60 Hz, AC interference and effects inputs 1 & 2 equally. |
Common Mode Rejection Ratio | The degree in which an amplifier will reject a common mode signal. |
Uses a 3 prong conductor cord with color code and must limit leakage of current. | Power Cord. |
Power Supply | Has On/Off switch. Always On. Should be properly fused and protected with circuit breaker. |
The power cord helps to... | Limit leakage current. |
The ground connection in the wall receptacle to insure electrical safety must be connected to... | The building ground. |
Parallel resistors cause voltage to be... | Constant in all resistors. |
Power is measured in... | Watts. |
Fuses blow because... | A pre-computed critical temperature is reached. |
Direct Current | A steady flow of current flowing in one direction. |
Where is direct current found? | Europe. |
Alternating Current | Current that alternately flows in one direction and then in the other and involves 60 Hz AC, which completes and entire cycle. 1/2+, 1/2-. U.S. |
Semiconductors | Neither good conductors, nor good insulators. |
What is the basic unit of Electricity? | Electromotive Force (E), measured in Voltage (V). Current (I), measured in Amperes (A). and Resistance (R), measured in Ohms (Ω). |
What is Electromotive Force measured in? | Voltage (E). |
Variable Resistors | Resistors that vary on a continuous scale. |
What is an example of a Variable Resistor? | Dimmer switch or sensitivity adjust. |
Circuit Breakers | Better than fuses because they don't have to be replaced. Stops current flow when some critical power level is exceeded. |
What are considered to be conductors? | Copper (Cu), Silver (Ag), Gold (Au), Platinum (Pt), Tin (Sn), Iron (Fe). |
What unit is resistance measured in? | Ohms (Ω). |
What do a string of resistors form? | A voltage divider (on-off switch). |
What type of test would you use 1,000th of a volt? | EKG's and EMG s. |
Time Constant | The time it takes for a signal to decay to 37% of it's original height. |
The notch filter works similar to a... | Frequency Response Curve. |
The Time Constant is like the process of... | Charging a battery. |
Capacitance is used for... | To store electrical energy. |
Phase Shift | (HFF) Not only attenuates output, but when compared to input, shifts the occurrence in time to the right and then appears to be occurring later in time. |
Transformer | When two coils are adjacent to each other, the flow of current in one coil generates a magnetic field that induces current flow. |
Capacitive Reactance | When AC is placed across a capacitator that is alternatively charging and discharging. CR is the time required for the charge and discharge causing opposition. |
What is the meter called that measures volts? | Voltmeter. |
The time it takes for 1 microfarad capacitator to charge to 63% of it's full scale charge is called... | Time Constant. |
What is Rise Time? | The time it takes to store up to 63% of a full scale. (Charging part of Time Constant). |
What does inductance oppose? | Any change in current. |
What is inductance measured in? | HENRY. |
What is the symbol of inductance? | L |
What is a practical inductor? | Coils. The more turns, the larger the inductance. |
What impedes current flow? | Capacitive Reactance. |
What does inductive reactance do? | Lowers total voltage. |
Where does zero voltage exist? | Only at the earth. |
What is a circuit ground? | A common connection of electronic circuitry. |
Gain | Amplification factor. |
Current is measured in... | Amperes. |
Resistors are... | Elements that do not give up electrons easily. |
Insulators are... | Materials that, even with a strong electrical force, will not give up electrons easily. |
Name insulators. | Plastic, glass, porcelain, rubber, air. Some plastics will be destroyed by excessive EM or voltages. |
Name a material that is not an insulator. | Silicon. |
Name another material that is not an insulator. | Gold. |
Silicon is a... | Semiconductor. |
Electromotive force is measured in... | Voltage. |
Resistance is measured in... | Ohms. |
An Evoked Potential (EP) is measured in... | Nanovolts. |
Phase Shift | Any change that occurs in the phase of one quantity, or in the phase difference between two or more quantities. |