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Physic2 x-ray ciruit
| Question | Answer |
|---|---|
| Autotransformer measures in | volts |
| What is the purpose of a step-up transformer | electromagnetic; increase volts |
| What is the purpose of a step-down transformer | increases amperage |
| Where is the kVp selector located | attached to the secondary of the autotransformer |
| Where is the pre-reading voltmeter located | secondary of autotransformer connected in parallel |
| Where is the exposure switch and timer located | between the secondary of the autotransformer and the primary of the step-up transformer |
| Where is the mA meter located | connected in series in the middle of the secondary of the step-up transformer |
| Where is the rectification system located | Between the secondary of the step-up transformer and the x-ray tube |
| Where is the filament ameter located | connected in series on the primary side of the step-down transformer |
| What are table tops made of | carbon fiber, floating Tops, 90/30, and bucky slot cover |
| What absorbs very little of the primary beam | carbon fiber |
| Fluoroscopy tables that tilt____ degrees to the feet and _____ to the head | 90;30 |
| Where is the line voltage compensator located | on the primary side of the autotransformer |
| What does the line voltage compensator do | It adjust the voltage(as there are are variations in line voltage sometimes) so that a consistent level of voltage is always supplied to the autotransformer |
| The filament circuit contains a mA selector called a | rheostat |
| The filament circuit contains a step down transformer whos purpose is to | increase amperage to the filament of the x-ray tube |
| The filament circuit contains a | Filament ammeter |
| The mA selector and the filament ammeter are both located where | on the primary side of the step down transformer |
| Where is the timer located | between the secondary side of the autotransformer and the primary side of the step up transformer |
| Timers are located in the | tube circuit |
| What kind of timer is very simple and used in smaller uits | mechanical timer(cheap but not very accurate) |
| Mechanical timers can only be used for exposures greater than | 250 milliseconds |
| What type of timer has a synchronous motor and is synchromized with a 60 current cycle | Synochronous timers |
| The shortest exposure time that can be used is___ second and the time steps increase multiples of 1/60 is__,___ | 1/60;1/30,1/20 |
| These are the most sophisticated, most complicated, and most accurate | Electronic timers |
| This is the most common type of timer used | Electronic timers |
| The electronic timer has a exposuretimes avaliable as low as | 1 millisecond |
| These timers are electronic timers that monitor the product of mA and time and terminate the exposre when the proper mAs is reached | mAs timers |
| Where is the mAs timer located | on the secondary side of the step-up transformer |
| What knid of timer automatically shuts the system of when the exposure is done | phototimer |
| Whjat is rectification | Voltage polarity control |
| The x-ray tube will work well is the cathode is always___ and the anode is always___ | negative and positive |
| Since the current is A.C. rectification only happens in | half the time |
| Rectification makes sure that the voltage is always | being fed from cathode to anode in the x-ray tube |
| This is where the x-ray tube rectifies itself | self rectification |
| Where is self rectification found | in small portables and can only handle low techniques |
| Electrons flow through a | single rectification circuit |
| This type of rectification uses either one or two valve tubes(thermionic diodes) | half wave rectification |
| This will stop the current from reaching the anode on the reverse bias | half wave rectification |
| During the half wave rectification the reverse bias is | eliminated |
| What will allow higher techniques than self rectification | half wave rectification |
| This uses four valve tubes and solid states rectifiers | full wave rectification which is called the graetz bridge rectification |
| this will allow the voltage to be fed from cathode to anode in the x-ray tube | full wave rectification |
| converts alternating current to direct current | rectification |
| Valve tubes in rectification are | thermonic diodes |
| solid state diodes in rectification are | P-N junction |
| High frequency generators are used to replace what? | Full wave or three phase rectification |
| What is the advantage of a high frequency generator | That they provide a nearly constant potential voltage waveform and are very small |
| How much of a ripple do high frequency generators have | 1% |
| Where can high frequency generators be placed | because they are small insize they can be placed in the tube housing |
| What are the results of a high frequency generator ripple | because it is almost constant potential it results improved image quality and lower patient dose |
| If the high frequency generator uses an inverted circuit what happens | high speed switches or choppers which convert DC into a series of square pulses |
| What is the self rectification ripple | 200% ripple |
| Half wave rectification | 100% ripple |
| Full wave rectification | 100% ripple |
| 3 phase- 6 pulse | 13% ripple |
| 3 phase- 12 pulse | 4% ripple |
| high frequency | less than 1% ripple |
| steady direct current | 0% ripple |
| What does a spinning top test do | evaluate the accuracy of the timer and makes sure the rectification system is working properly |
| What is the spinnning top test used to test | full wave rectification and halewave/ self rectification |
Created by:
atesta0824
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