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RAD 231 Unit 1 proto
| Question | Answer |
|---|---|
| X-ray generator runs on ____ voltz or higher | 220 voltz |
| the study of moving electrical charges | electrodynamics |
| is the ability to do work because of a separation of charges and is measured in volts | Electrical potential |
| is an expression of the flow of electrons in a conductor and is measured in amperes. | Current 6.25 x 10^18 |
| is that prroperty of an element in a circuit that resists or impedes the flow of electricity and is measured in ____. | Resistance, ohms |
| defined as a difference in electrical potential energy between two points in a electric curcuit. | potential difference |
| defined as the amount of electric charge flowing per second | current |
| low resistance = ___ free electrons. Conductor length is (short/long) Diameter is (small/large) temperature is (low/high) | low resistance = more free electrons. Conductor length is short Diameter is large temperature is low |
| High resistance = ___ free electrons Conductor length is (short/long) Diameter is (small/large) temperature is (low/high) | High resistance = fewer free electrons Conductor length is long Diameter is small temperature is high |
| is a propterty of circuit which opposes or hinders the flow of an electric current. Measured in ____ | Resistance measured in ohm |
| states that the potential difference (voltage) across the total circuit or any part of that circuit is equal to the current (amperes) multiplied by the resistance. | ohm's law |
| is a device that produces electrons through a chemical reaction, stores an electric charge for the long term, and provides an electric potential. | a battery |
| is a device that is like a battery in that it stores an electric charge, but works very differently in that it cannot produce new electrons and stores the charge only temporarily. | Capacitor |
| is a "one-way valve" device and allows electrons to flow in only one direction. | Diode |
| is simply a section of specail wire, usually encased in glass, that quickly melts if the current flow rises excessively, thus opening the circuit. | Fuse |
| acts if the current flow rises excessively, the _____ internal switch is tripped (opened), stopping the flow of electricity. | circuit breaker |
| is a device designed to inhibit the flow of electrons, thereby precisely regulating the flow of electricity through that part of circuit where it is placed. | Resistor |
| is simply an adjustable or variable form of resistor. mA selector by adjusting the rheostat. | rheostat |
| is a device that opens a circuit (breaks the pathway). | switch |
| is a device that can increase or decrease voltage by a predetermined amount. | transformer |
| part of the circuit connected to the primary coil of the transformer is the ____ or _____ voltage circuit. | Primary or low voltage circuit. |
| prt of the circuit connected to the secondary coil of the transformer is the ___ or ___voltage circuit. begins w/ the high voltage step-up transformer. fixed ratio. wires off this circuit are __to reduce insulation b/c higher voltage means less current. | Secondary or high voltage circuit. smaller |
| relationship between electricity and manetism. 2 types are self induction and mutual induction | electromagnetism |
| Induced currents flow away from the action that induced it (changing magnetic fields) | Lenz law |
| the emf induced in the secondary coil is to the emf in the primary coil, as the number of turns in the secondary coil is to the number of turns in the primary coil. | transformer law |
| a transformer, having more turns in the secondary coil than in the primary, puts out higher voltage than is supplied to it and is therefore a ____ | step-up transformer N;s/N;p |
| If the secondary coil has fewer turns than the primary coil, the output voltage will be less than the input voltage, and the transformer is a _____ | step-down transformer |
| step-up transformer increases the voltage, but decreases the ____ in an inverse ratio | amperage |
| premits adjustment of the line voltage to the correct value. | line voltage compensator |
| is a device that varies input voltage to a transformer to control its output voltage. controlled by the kilvolt peak selector on the operating console. operates on principle of self induction. Only 1 coil of wire and central magnetcore. | Autotransformer |
| most diagnostic equipment is supplied with a special radiographic-fluoroscopic ________, enabling the radiologist to do spotfilm work automatically. Automatically selects teh exposure factors for radiography when shifting the spotfilm into radiographic | Changeover switch |
| corrects for instantaneous fluctuations in line voltage that may be caused by momentary demand elsewhere on the line, such as in the starting of an elevator or air conditioner. | filament stabilizer |
| is set to terminate teh exosure in the event of failure in the automatic circuit, to avoid the hazard of over-loading the tube or overexposing the patient | back up timer |
| hand-held timer has a clock mechanism where turning the knob to the selected time; activating the exposure button releases the spring and terminates the exposure at the preselected time interval. | Mechanical timer |
| an electrical device which converts an alternating current into a direct one by allowing a current to flow through it in one direction only. | rectifier |
| The process in which a changing current in one coil induces emf in other coil | mutual induction |
| phenomenon in which a changing current in a coil induces an emf in itself is called | self induction |
| is simply an on-off switch for the unit and is connected to the power supply of the facility. can be double blade, located on the wall | main power switch |
| begins exposure by closing the switch to start and stops exposure by opening the switch | exposure switch |
| _______ is a device usually wired to the ________ and automatically adjusts the power supplied to the x-ray machine to 120-220 volts. Although most have 220v | line compensator is a device usually wired to the autotransformer |
| are included in the primary circuit to protect against short circuits and electric shock. | circuit breaker |
| ______ends with the "primary side of the high voltage transformer". | Primary circuit |
| located on the primary side; in parallel with the autotransformer to measure voltage across 2 points (major and minor kVp selectors) | Kilovolt meter |
| special gas-filled triode that becomes conductive at a particular, critical voltage | thyratron |
| a solid state device that functions to become conductive at a particular voltage but can provide much shorter and more accurate exposures. | thyristor |
| RC is | resistance x capacitance |
| used in order to measure the filament current, and hence the amount of heat developed in the filament. Connected in sereies in the filament circuit | Filament ammeter |
| automatically adjusts the filament current to maintain constant mA over a wide range of kV; | space charge compensator |
| When a ______ charge is placed on the "P" side and a _____ charge on the "N" side, the diode will conduct electricity. | Positive, negative |
| When a ______ charge is placed on the "P" side and a _____ charge on the "N" side, the diode will NOT conduct electricity. | Negative, Positive |
| uses two rectifiers in the electronic circuits to convert AC to DC. | Half-wave rectification |
| uses at least four rectifiers in the electronic circuit. | full-wave rectification |
| In a three phase power, each wave is generated and then phased so that each pulse is ___ degrees out of phase or out of step with the other waves. resulting in a waveform that never reaches zero | 120 degrees |
| pattern of wave worm, measures the amount of variation between maximum and minimum voltage | Ripple |
| the simplest type of rectification, the high voltage is applied directly to the terminals of the xr tube. | self-rectification |
| how many rectifers in a single phase | 2 rectifiers |
| how many rectifiers in a single or 3 phase | 4 rectifiers |
| Who am I? I keep current flowing from cathode to anode. Composition is a solid-state made of 2 semiconducting crystals, but i used to be a valve tube | Rectifier/diode |
| Who am I? I contain a high voltage transformer, filament transformer, rectifiers | High voltage generator |
| based on kVp changes, reduces exposure time by changing mA in increments | Falling load generator |
| this term refers to the process of stopping the discharge of the capacitor at some preselected point on the discharge curve. | wave tail cutoff |
| Power rating(kilowatt rating) = | power rating = (current/amps (I) x Voltz(kVp)) / 1000 |
| Disadvantage of a 3 phase power is? | initial cost |
| electromagnetic induction is the process of causing an electrical current to flow in a conductor: | when it is placed in contact with another conductor |
| Self induction is used in operation of what device? | autotransformer |
| the strength of the magnetic fields in a transformer is increased by: | coiling the wires and letting their magnetic fields overlap |
| what type of current is required for proper operation of the x-ray tube? | Direct |
| what type of x-ray machine uses a continually decreasing mA for the shortest times possible? a. ionization chamber b. portable c. C-arm d. falling load generator | d. falling load generator |
| electrostatic charges concentrate on a conductor in the area of (least/greatest) curvature | greatest curvature |
| a magnetic field (always/never) surrounds an electrical charge in motion | always |
| a _____ allows the flow of electrons | conductor |
| the ____ is the unit of potential difference | volt |
| the path of electrical current is called? | circuit |
| electricity is supplied to the imaging department by a: a. motor b. rectifier c. generator d. voltmeter | generator |
| A generator at the power company converts mechanical energy to electrical energy. A ____ converts electrical energy to mechanical energy | motor |
| the electricity provided to the radiology department is: | 60 Hz AC |
| the electricity provided to the radiology department operates at: | 120 pulses per second |
| high-frequency power: a. is less effective than single-phase power b. has almost no ripple c. has more ripple than three-phase power d. is yet unproven | b. has almost no ripple |
| the primary advantage of three-phase power is that: a. voltage drops to zero only 6 times per sec b. voltage drops to zero only 12 times per sec c. voltage never drops to zero d. voltage is always at peak value | c. voltage never drops to zero |
| a variable transformer that is used to select kVp for the x-ray circuit is the: a. step up transformer b. autotransformer c. step-down transformer d. rectifier | b. autotransformer |
| a transformer that has more turns in the secondary coil than in the primary coil is called a: a. step-up transformer b. solenoid c. step-down transformer d. filament transformer | a. step up transformer |
| what is the transformer used to boost voltage to kilovoltage levels called? a. autotransformer b. step down transformer c. step up transformer d. low voltage transformer | c. step up transformer |
| voltage coming to the x-ray machine is kept constat through the use of? a. autotransformer b.step down transformer c. rectifier d. line voltage compensator | line voltage compensator |
| a step down transformer: a. steps down voltage b. steps down current c. steps up voltage d. steps up resistance | a. steps down voltage |
| Where does thermionic emission occur? a. step-down transformer b. rectifier c. cathode d. timer | c. cathode |
| which of the following devices is prereading? a. step-down transformer b. rectifier c. timer d. kVp meter | d. kVp meter b/c it indicates what the voltage will be after being stepped up. hence it is prereading. |
| which device reduces voltage and provides current to produce an electron cloud or space charge at the filament? a. step-down transformer b. rectifier c. cathode d. timer | a. step down transformer |
| which device is electronic, with a setting as low as 0.001? a. step-down transformer b. rectifier c. cathode d. timer | d. timer |
| what changes AC to DC? | rectifier |
| which of the following is composed of solid-state silicon-based diodes? a. stepdown transformer b. rectifier c. cathode d. timer | b. rectifier |
| what regulates the duration of x-ray production? a. stepdown transformer b. rectifier c. cathode d. timer | d. timer |
| what is located in teh x-ray circuit between the high-voltage transformer and teh x-ray tube? a. stepdown transformer b. rectifier c. cathode d. timer | b. rectifier |
| which of the following measures tube current? a. anode b. mA meter c. ionization chamber d. falling load generator | b. mA meter |
| what device uses maximum heat storage ability of the tube to deliver mAs? a. anode b. mA meter c. Ionization chamber d. Falling load generator | d. falling load generator |
| what device increases voltage approximately 500 times? a. anode b. mA meter c. Ionization chamber d. step-up transformer | d. step-up transformer |
| what device always delivers the shortest exposure time possible? a. anode b. mA meter c. Ionization chamber d. falling load generator | d. falling load generator -coupled w/ an electronic timer, this results in times as short as 1/1000 sec |
| the filament is kept warm by: a. a standby current from the time the x-ray machine is turned on b insulating coil c. lead housing d. current produced only during exposures | a. a standby current from the time the x-ray machine is turned on |
| single phase, full wave rectification produces a. diret current b. pulsating direct current c. pulsating direct current with 120 pulses per sec d. pulsating direct current with 120 pulses per second and 100% ripple | d. pulsating direct current with 120 pulses per second and 100% ripple |
| three-phase, 12 pulse full-wave rectification produces: a. direct current with 13% ripple b. direct current with 4% ripple c. direct current with 100% ripple d. alternating current with 13 % ripple | b. direct current with 4% ripple |
| A transformer operates by the principle of: a. Static induction b. Mutual induction c. Secondary induction d. Electrodynamics Induction | b. mutual induction |
| What is the formula for electrical power in watts? | P = IV |
| Transformers are used in electrical circuits to: | Change the voltage and current into higher or lower values |
| A step-down (Coolidge) transformer is most likely to be found in the: | filament portion of the primary circuit |
| The purpose of the _____ in the filament circuit is to allow the operator to vary the current in the circuit. a. Capacitor b. Rheostat c. Autotransformer d. Step-down transformer | rheostat |
| The part of the x-ray generator that supplies the current and voltage to the cathode of the x-ray tube is called the: a. Filament circuit b. Main x-ray circuit c. High voltage circuit d. Thyromagnetic circuit | a. filament circuit |
Created by:
Btran573