Biomedical Engineering Reference
In-Depth Information
Our research team has so far successfully developed [
2
-
5
] electronic passive
(R, C, and L) and active component diodes along with some simple digital and
analog circuits.
In this communication, we report realization of the flowing human blood
transistor device. The effect of variables like blood temperature, blood flow rate,
distance between the forming probes on the input and output characteristics as well
as current gain factor b of the transistor is studied.
Physical Model of Flowing Human Blood-Based Transistor
The experimental setup comprises mechanical and electronic transistor architec-
ture systems as under:
1. Mechanical system: Consists of a glass vessel (tank supported by a wooden
stand) containing human blood (group B+), from where the blood flows through
a capillary tube, which in turn passes through another glass vessel containing
water. External water reservoir supplies water at desired temperatures to this
vessel. This capillary tube is further extended horizontally through which the
blood at desired temperature passes. The blood after passing through this
horizontal capillary tube portion proceeds toward the sink vessel where it is
collected. The height of the tank controls the blood flow rate (Fig.
1
).
2. Electronic transistor architecture: The transistor has two diodes in back-to-
back configuration, one formed by blood inserted set of two probes 1-2 and
second, by blood inserted another set of two probes 3-4. The geometry and
distance between forming diodes (set of two probes) as well as spacing between
probes 2 and 3 play vital roles in the development of the transistor. The input
circuit contains variable voltage power supply along with current measuring
multimeter to realize voltage/current (V
BE
,I
BE
) between base and ammeter.
Similarly, output circuit is realized by another variable voltage supply and
resulting current (V
CE
,I
CE
), between collector and ammeter. The transistor
manifested technically acceptable input and output characteristics of the device
including the current gain factor b variation.
The effects of variable parameters of (1) temperature, (2) distance between
probes 1-2-3-4, and (3) flow rate (drops/min) of the blood transistor were studied
while conducting development of this transistor configuration.
Method of Measurement for Input/Output Characteristics
1. For Input Characteristics: Varying voltage V
BE
between probes 1 and 2 was
applied while keeping voltage V
CE
between probes 3 and 4 constant. During
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