Feed-back, means a reaction to a stimulus, I will explain, the concept is simple, but explanation is a bit troubled, bio-feedback is to electronically feed back a user through sound or Visual, it is possible to control your meditation state, causing the user to reach a pre-established state at any time.
Simple Bio-Feedback Circuit Diagram
With this circuit it is possible to feedback from consciously varying the resistance of the skin, even though the equipment helps, even so will require training for this.
In order to use the biofeedback, the user must remain at rest, preferably lying down, since physical activity and variations of the emotional state influence the resistance of the skin, regardless of our will or unconsciously.
The biofeedback electrodes should be attached to the ring finger and index finger by tape or tape, and the hand should be in a comfortable, stationary position.
How Bio-Feedback Works
The biofeedback has as its main component an integrated circuit 555, configured as an astable multivibrator. The oscillation frequency of the 555 depends directly on the values of C1 and the collector current of Q1, which is connected as a current generator.
The resistors R1 and R2 attached to its base form a resistive divider which together with R3 and R9 determine the collector current of the transistor.
When the person connects the electrodes, the skin resistance is placed in parallel with R2, which changes the frequency of the oscillator. If skin resistance increases or decreases, we will see a drop or increase in the oscillation frequency of Cl1. R8 functions as volume control for Q3, which is the power amplifier.
Relation of Bio-Feedback Components
R1 – 47 kOhm x 1/4 Watt
R2 – 680 kOhm x 1/4 Watt
R3, R4, R6 – 1 kOhm x1/4 Watt
R5 – 22 kOhm x 1/4 Watt
R7 – 10 kOhm x 1/4 Watt
R8 – 50 kOhm – potentiometer linear
R9 – 10 kOhm – trimpot
C1 – 100 ηF pollster
C2 – 10 ηF pollster
CI1 – NE 555 ou equivalent
Q1 – BC 178 ou equivalent
Q2 – BC 549 ou equivalent
Q3 – 2N3055 ou equivalent
The biofeedback power is provided by a 9 Volt battery, but a well filtered source to avoid noise can be used without problems.
Source New Electronic Magazine 1 of 1977 - author of Gary Gronich.
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