Question

DC amplifiers are employed with  _______ feedback type.

(a) positive

(b) negative

(c) depends on the application

(d) can be any positive or negative does’t matter

I had been asked this question during an internship interview.

The above asked question is from Preamplifiers topic in portion Recording System of Biomedical Instrumentation

Answer 1

Right option is (b) negative

Explanation: DC amplifiers are generally of the negative feedback type. They are used for medium gain applications down to about 1 mV signal levels for full scale. They are not practical for very low level applications because of dc drift and poor common-mode rejection capabilities.