| Biomedical Instruments are | made from basic electronic components connected to build more complex electronic circuits with special function. |
| Biomedical instrumentation and engineering | application of knowledge and technologies to solve problems
related to living biological systems.
It involves diagnosis, treatment and prevention of disease in human. |
| An electronic component | is any basic discrete device or physical entity in an electronic system used to affect electrons or their associated fields |
| Basic
electronic components are: | Resistors
Capacitors
Inductors
Transistors
Diodes and LEDs
Amplifiers
Integrated Circuits |
| Basic electronic circuitry is similar in both simple and complex apparatuses but what is different | entirely different purposes |
| Resistor | Resist the current - consuming power |
| Laws applied for calculating resistor | Ohms Law |
| Property of resistor | resistance (R) |
| unit of resistor | ohm |
| what does it mean when resistors are passive | they contain no source of power or amplification but only attenuate or reduce the voltage or current signal passing through them |
| what are resistors are used for | resistor to control the voltages and the currents in your
circuit (either limit current or allow for a drop-in voltage). |
| Resistor | passive electronic devices that resist the flow of current |
| Passive components consume what | electrical energy |
| Passive components used in | electrical and electronic circuits can be
connected in an infinite number of ways |
| biomedical instrument
consists of the following
functional basic parts: | Measurand
Sensor / Transducer
Signal Conditioner
Display
Data Storage and Data
Transmission |
| ACTIVE COMPONENTS | HAVE DIRECTIONALITY |
| active component examples | Semiconductor devices-transistors |
| PASSIVE COMPONENTS | (HAVE NO
DIRECTIONALITY) |
| examples for passive components | Resistors, capacitors, inductors, diodes
diodes and polarized capacitors must be installed in a specified way |
| differences between active and passive components | active-
inject power into a circuit
capable of electrically controlling
amplify the flow of electrical current |
| differences between active and passive components | passive components
either consume or store energy |
| Resistor color codes | 1 st band = 1 st number
2 nd band = 2 nd number
3 rd band = # of zeros / multiplier
4 th band = tolerance |
| capacitor | Temporarily store an electric charge – battery with very low
capacity |
| how capacitance is defined | as the ratio of the electric charge Q
on each conductor to the potential difference V between them |
| what capacitors are used for | Introduce a time-delay in a circuit, removing noise, or making
the supply voltage of a circuit more stable |
| If a component needs an
immediate supply of electrons, | the capacitor can supply those
electrons. |
| Capacitors can smooth out a
signal | eliminate the ripples
or spikes in DC voltage. |
| The capacitor can absorb | the peaks and fill in the valleys of a rippled signal. |
| what is inductor | is similar to the opposite of a capacitor. |
| in series inductors will | resist alternating currents (AC) and let direct currents (DC) flow free. |
| difference between series connection and parallel in resistors | Rseries= r1+r2+...
Rparallel=1/R1+1/R2... |
| difference between series connection and parallel in inductors | Lseries=L1+L2...
Lparallel=1/L1+1/L2... |
| difference between series connection and parallel in CAPACITORS | Cseries= 1/C1+1/C2+...
Cparallel=C1+C2+... |
| WHAT IS transistor | a semiconductor component used to amplify
and switch electronic signals and electrical power |
| what will happen A voltage or current applied
to one pair of the transistor’s terminals | changes the current through another pair of terminals. |
| A transistor is composed of | semiconductor material with at
least three terminals for
connection to an external
circuit. |
| Transistors have 3 pins. For
these transistors: | Collector
Emitter
Base |
| Types of
transistors | B I P O L A R J U N C T I O N T R A N S I S TO R
F I E L D- E F F E C T T R A N S I S TO R . |
| Bipolar junction | U S E F U L A S A M P L I F I E R S .
ex: C O L L E C TO R ,
E M I T T E R , B A S E |
| Field-effect transistors | useful as motor drivers
ex: source, drain, gatemosfet |
| N P N ( N- C H A N N E L F E T ) V E R S U S
P N P ( P - C H A N N E L F E T ) | NPN versus PNP is how the semiconductors are layered.
NPN: Not pointing in
PNP: Pointing in permanently |
| what is diode | ◦ A diode is a one way valve (or gate) for
electricity |
| what is diodes component | with an
asymmetrical transfer characteristic |
| what does diode has | has low (ideally zero) resistance in one
direction, and high (ideally infinite) resistance
in the other direction. |
| Diodes will protect your | electronics |
| Diodes have a bar | on the cathode (negative) side. |
| LED diode | LIGHT EMITTING DIODE (LED) IS A SEMICONDUCTOR LIGHT SOURCE. |
| WHEN ELECTRICITY IS
PASSING THROUGH THE DIODE, | IT
EMITS LIGHT. |
| amplifier | EFFECTIVELY THE OPPOSITE OF AN ATTENUATOR: WHILE AN AMPLIFIER PROVIDES GAIN, AN ATTENUATOR PROVIDES LOSS. |
| AMPLIFIER QUALITY IS CHARACTERIZED BY A LIST
OF SPECIFICATIONS THAT INCLUDES: | gain
bandwidth
efficiency
linearity
noise
output dynamite range
slew rate
rise time stability |
| gain | the ratio between the magnitude of output
and input signals |
| bandwidth | the width of the useful frequency
range |
| Efficiency | the ratio between the power of the
output and total power consumption |
| Linearity, | the degree of proportionality between
input and output |
| Noise | a measure of undesired noise mixed into
the output |
| Output dynamic range, | the ratio of the largest and the smallest useful output levels |
| Slew rate | the maximum rate of change of the
output |
| Rise time | , settling time, ringing and overshoot
that characterize the step response |
| Stability | the ability to avoid self-oscillation |
| Types of amplifiers | Voltage amplifier
• Current amplifier
• Transconductance amplifier
• Trans resistance amplifier |
| ohms law | Describes the relationship between
current, voltage and resistance |
| Kirchhoff‘s current law | Sum of all currents going in and out of the
node is equal to 0 |
| current that enter the node | have + sign, currents that leave the node have – sign. |
| KIRCHHOFF‘S VOLTAGE LAW | SUM OF ALL VOLTAGES IN A CIRCUIT
EQUALS 0 |
| THE VOLTAGE SIGN (+/-) | IS THE
DIRECTION OF THE POTENTIAL
DIFFERENCE |
| The resistor colour code markings are always read one band at a time. Starting
from | the left to the right, with the larger width tolerance band oriented to the right side indicating its
tolerance |
| how capacitors | The current through a capacitor can be changed instantly, but
it takes time to change the voltage across a capacitor. |
| Typical capacitance values range from | m about 1 pF (10−12 F) to about 1 mF (10−3 F). |
| What are Inductor USED FOR | stores energy in the form of a magnetic field, usually by means of a coil of wire |
| RESISTANCE | U=I*R |
| INDUCTANCE | u(t)=L*di(t)/dt |
| CAPACITANCE | i(t)=C*dv(t)/dt |
| Diode | switch, two-terminal electronic component that conducts primarily in one direction |
| LED | component that can give light
to give a visual feedback from our circuit |
| amplifier | increases the power of a signal |
| The four basic types of amplifiers are asfollows: | voltage
current
transconductance
trans resistance amplifier |
| Capacitors can also be connected together in various series and parallel combinations to form | capacitor networks. |
| what are transistors used for | to give a visual feedback from our circuit. |
| Voltage amplifier | This is the most common type of amplifier. An input voltage is
amplified to a larger output voltage. The amplifier's input impedance is high and the output impedance is low |
| Current amplifier | This amplifier changes an input current to a larger output current. The
amplifier's input impedance is low and the output impedance is high. |
| Transconductance amplifier | This amplifier responds to a changing input voltage by
delivering a related changing output current. |
| Trans resistance amplifier – | This amplifier responds to a changing input current by
delivering a related changing output voltage. Other names for the device are
transimpedance amplifier and current-to-voltage converter. |
| Not all amplifiers are the same and are therefore classified | according to their circuit configurations and methods of operation. |
| There are many forms of electronic circuits classed as amplifiers | from Operational Amplifiers
and Small Signal Amplifiers up to Large Signal and Power Amplifiers. |
| The classification of an amplifier | depends upon the size of the signal, large or small, its physical configuration and how it processes the input signal that is the relationship between input signal and current flowing in the load. |
| An integrated circuit | is a set of electronic circuits on one small plate
("chip") of semiconductor material, normally silicon. |
| integrated circuit used for | It could be an amplifier, it could be a microprocessor, it could be a USB
to serial converter. It could be anything! |
| electric charge | generates electric field. the electric charge influences other electric charges with electric forces and influenced by the other charges with same force in the opposite direction |
| electrical voltage | electrical voltage is defined as electric potential difference between two points of an electric field |
