3 Circuits

Question 1

What are the 3 things a PSU must be?

Answer 1

1. Electrically safe (as per IEC 60601-1)
2. Provide means of protection for the operator and patient
3. Have low leakage current (as per IEC 60601-1)

Question 2

What are the 4 important criteria when select a PSU?

Answer 2

1. Output voltage and current
2. Power rating
3. Form factor
4. Thermal management

Question 3

What do medical grade inlet filters do?

Answer 3

Help reduce conducted emissions

Question 4

What is leakage current?

Answer 4

Any current that is non-functional
This could be current that flows from the intended circuit to ground, the chassis, or other conductive parts

Question 5

What does ferrite do?

Answer 5

Reduces high frequency noise
The ferrite’s reactance increases at higher frequency which reduces unwanted noise