PRACTICAL NO: 3

Aim: To study EMG SIMULATOR & STIMULATOR.

Material required:

[1] Matrix trainer kit-EMG SIMULATOR & STIMULATOR.

[2] DIGITAL STORAGE CRO.

Procedure:

Setup-

[1] Keep the POWER switch in off condition.

[2] Connect power chord to mains (230 volts A.C).

[3] Connect CRO at the output at T1 w.r.t Ground T2.

[4] Set the required rate by P1.

Experiment-

[1] Put on the trainer & CRO.

[2] Note the output waveform.

[3] Select X10 MODE on CRO note voltage waveform across T4 w.r.t T3

(Jumper J1 at B)

[1]Note waveform amplitude across T4 w.r.t T3.

Observation:

ENG SIMULATOR & STIMULATOR

INTRODUCTION:

A system is able to produce signals, as some other system is known as simulator.

Biomedical simulator is those are producing artificial signal, like nature part produce

in live body. The Contraction of skeletal muscle results in the generation of potentials

in individual muscle. The action potential lasting only for few milliseconds. The

electrical activity of the under lying muscle mass can be observed by means of surface

electrodes on the skin. In voluntary contraction of skeletal muscle, the muscle

potential range from 50µV To 5mV and duration 2 to 15mS.

This signal known as the Electromyogram. This signal is artificially generated by

means of electronics components by EMG simulator.

STIMULATOR: stimulator used to stimulate muscle under test. Stimulator provide

single or double or train of pulse. Stimulator amplitude, duration, repetition & delay

are adjustable. The o/p is either constant voltage & constant current type. The

constant voltage type stimulator provides rectangular pulse with amplitude 0-500V.

CIRCUIT DESCRIPTION:

Fig3.2 show circuit of EMG STIMULATOR & SIMULATOR. It consists of a pulse

generator based on time: IC LM555. The frequency of oscillation is variable through

P1.

Jumper J1 disable stimulator o/p when it is on a position. This jumper breaks power

supply to switching transistor through Q1.

When jumper J1 on a position circuit works only as EMG stimulator. Combination

differentiator integrator circuit by C4,R3 & C5, does this. The signal looks like as

below.

TYPICAL EMG SIGNAL:

Fig.3.1: EMG signal

When juper J1 on B position transistor Q1 coupler power supply to transistor Q2

through pulse transformer Tx1. Each pulse differentiates by C2 and D1 and switch on

q1. Moment Switching ON of Q2 produce High voltage Stimulator pulse across

secondary of TX1 (TX1 is a step-up transformer with 1:30 ratio).

This output is used to stimulate Nerve at the time of EMG.

Figure: 3.2: EMG SIMULATOR AND STIMULATOR

Conclusion: