CABT Fundamentals of Electronics Questions and Answers — Questions and Answers
Question 1: A biomedical technician is servicing a defibrillator and notices the time it takes to deliver a shock is significantly delayed. This issue is most likely related to a failing component responsible for storing electrical charge. Which of the following electronic components is the most probable cause?
- Resistor
- Capacitor (Correct answer)
- Diode
- Transistor
Correct answer: Capacitor
Capacitors are fundamental electronic components that store electrical energy in an electric field. In a defibrillator, a large capacitor is charged to a high voltage and then rapidly discharged to deliver the therapeutic shock. A failing capacitor would struggle to store the necessary charge or discharge it effectively, leading to performance issues like a delayed shock.
Question 2: According to Ohm's Law, if the voltage supplied to a medical device remains constant but the resistance of a specific circuit within it increases, what is the expected effect on the current?
- The current will increase.
- The current will remain unchanged.
- The current will decrease. (Correct answer)
- The current will become alternating.
Correct answer: The current will decrease.
Ohm's Law states that the current (I) flowing through a conductor is directly proportional to the voltage (V) and inversely proportional to the resistance (R), expressed as I = V/R. Therefore, if the voltage (V) is constant and the resistance (R) increases, the current (I) must decrease.
Question 3: A technician is troubleshooting a patient monitoring system where a very weak physiological signal (like an ECG) is not being displayed correctly. The issue is likely in the amplification stage. Which component is specifically designed to amplify such weak signals with high precision in medical instruments?
- A transformer
- A fuse
- A relay
- An operational amplifier (Op-Amp) (Correct answer)
Correct answer: An operational amplifier (Op-Amp)
Operational amplifiers (Op-Amps) are essential components in medical instrumentation for amplifying weak biological signals, such as those from an ECG or EEG. They provide the high gain, high input impedance, and low output impedance necessary to accurately boost these signals for processing and display without significant distortion or loss.
Question 4: Which of the following electronic components is a semiconductor device that allows current to flow in only one direction and is often used for rectification in power supplies for medical equipment?
- Inductor
- Capacitor
- Diode (Correct answer)
- Resistor
Correct answer: Diode
A diode is a semiconductor device with two terminals that essentially acts as a one-way switch for current. It allows current to flow easily in one direction (forward bias) but severely restricts current from flowing in the opposite direction (reverse bias). This property is fundamental for converting alternating current (AC) to direct current (DC), a process called rectification, which is crucial for powering most electronic medical devices.
Question 5: In a medical device's power supply circuit, an inductor is often used in conjunction with a capacitor. What is the primary function of the inductor in this filtering application?
- To store electrical charge.
- To oppose changes in current. (Correct answer)
- To block direct current (DC).
- To step up the voltage.
Correct answer: To oppose changes in current.
An inductor is a passive electronic component that stores energy in a magnetic field when electric current flows through it. Its fundamental property is to oppose any change in the electric current flowing through it. In power supply filters, this characteristic helps to smooth out the pulsating DC output after rectification, reducing ripple and providing a more stable DC voltage.
Question 6: A technician is working on a portable insulin pump. The compact size and low power consumption of the device's control circuitry are critical design features. These are made possible primarily by the use of which technology?
- Vacuum tubes
- Electromechanical relays
- Integrated circuits (Semiconductors) (Correct answer)
- High-capacity resistors
Correct answer: Integrated circuits (Semiconductors)
Integrated circuits (ICs), built from semiconductor materials, are the foundation of modern electronics, enabling the miniaturization and power efficiency required for portable and implantable medical devices like insulin pumps and pacemakers. They allow for complex circuits with millions or billions of transistors, amplifiers, and other components to be placed on a single tiny chip.
CABT Fundamentals of Electronics Questions and Answers
A biomedical technician is servicing a defibrillator and notices the time it takes to deliver a shock is significantly delayed.
This issue is most likely related to a failing component responsible for storing electrical charge.
Which of the following electronic components is the most probable cause?