Electronics and Electrical Safety Flashcards

What is the maximum allowable leakage current for a Type CF (cardiac floating) applied part according to IEC 60601-1?

Answer: 10 microamps

Type CF applied parts must have a maximum patient leakage current of 10 microamps under normal conditions to prevent microshock.

In a hospital electrical system, what is the purpose of an isolation transformer in an isolated power system?

Answer: To prevent ground-fault current from flowing through patients

An isolation transformer prevents ground-fault current from flowing through patients by electrically isolating the secondary circuit from ground.

What component in an electrical circuit allows current to flow in only one direction?

Answer: Diode

A diode is a semiconductor device that allows current to flow in one direction (forward bias) while blocking current in the reverse direction.

When measuring the resistance of a component with a multimeter, why must the circuit power be turned off first?

Answer: Because the multimeter supplies its own test current and external voltage will cause inaccurate readings

A multimeter in resistance mode supplies a small known current and measures the resulting voltage to calculate resistance. External circuit voltage would produce incorrect readings and could damage the meter.

What is the purpose of a ground wire (green or green/yellow) in a medical device power cord?

Answer: To provide a low-impedance fault current path to trip the circuit breaker

The ground wire provides a low-impedance path for fault current to flow back to the source, tripping the circuit breaker quickly and protecting patients and staff.

Which of the following best describes the function of an optocoupler (optoisolator) in medical equipment?

Answer: Transmitting signals between circuits while maintaining electrical isolation

An optocoupler uses an LED and photodetector to transmit signals between electrically isolated circuits, maintaining patient safety.