Question

Explain what is meant by the “driven right leg” circuit. What function does it serve? How is it modeled (include a figure) in a circuit schematic?

Answer 1

DRIVEN RIGHT LEG

A determined right leg circuit or DRL circuit is an electric circuit that is regularly added to natural sign intensifiers to decrease basic mode impedance.

FUNCTION

One of the difficulties related with making biopotential estimations is

dismissing the normal mode voltages to which the human body, cathodes, and

links are uncovered. That is the motivation behind why having an instrumentation intensifier

with high CMRR is significant.

Capacitive coupling of the 50/60Hz mains voltage is the primary wellspring of normal

mode obstruction. You can picture this circumstance as a patient (up until now

electrically drifting) associated with a 220Vrms at 50/60Hz voltage source by means of a

low worth capacitor.

This impedance heightens when the client/persistent is near electrical

hardware (an emergency clinic bed with bunches of bedside screens, a medical procedure room… ),

near an engine (in a treadmill, for example) or the framework utilizes long links

(vulnerable to higher coupling).

One method of lessening this impedance is by effectively driving the body back with

a known voltage with the goal that the body isn't electrically skimming any more. In its

essential execution a dc voltage could be driven yet the outcomes are improved

on the off chance that the body is driven back progressively relying upon the meddling normal

voltage. This is finished by continually observing the changing basic voltage the

two terminals are riding on head of. This voltage is reflected around the

reference voltage (normally a large portion of the flexibly) and driven back to the body.

In outline, as the body is capacitively pulled away from the reference voltage,

the RLD enhancer pulls it back in. It is generally named Right Leg Drive

since the driving is done in the piece of the body which is farthest from the

heart (the right leg).