to set up a common base transistor circuit project pdf

[srav.kum.1010]

Abstract:
In electronics, a common base (grounded-base) amplifier is one of the three basic topologies of single-stage bipolar junction transistor (BJT) amplifiers, typically used as a current buffer or voltage amplifier. In this circuit, the emitter terminal of the transistor serves as input, the output manifold and the base is grounded, or "common", hence its name. The field effect transistor analog circuit is the common gate amplifier.

Objective:

Study the input and output characteristics of a transistor in Common Base Configuration.

Components:

No: Name Quantity
1 :Transistor BC 107 1 (One)
2 :Resistors (1K) 2 (Two)
3: Breadboard 1 (One)

Equipment:

S.No. Name (Quantity)
1: DC power supply regulated double (0 - 30 V) 1 (Un)
2: Digital ammeters (0 - 200 mA) 2 (Two)
3: Digital Voltmeter (0-20 V) 2 (Two)
4 :Single strand conductors 2

Budget:

For transistor BC 107:

Maximum Collector Current = 0.1A
Vceo max = 50V

Circuit diagram:

H - Transistor parameter model CB:

Pin Assignment of Transistor:

View from the side of the pins

View from the top of the housing

Operation:

The bipolar junction transistor (BJT) is a three-terminal semiconductor device (emitter, base, manifold). There are two types of BJTs, namely NPN and PNP. It consists of two PN junctions, namely emitter junction and collector junction.

The basic circuit diagram for studying the input characteristics is shown in the circuit diagram. The input is applied between the transmitter and the base, the output is taken between the manifold and the base. the base of the transistor is common to the input and output and hence the name is the common configuration of the base.

Input characteristics are obtained between the input current and the input voltage at constant output voltage. It is represented between VEE and IE in constant VCB in CB configuration.

The output characteristics are obtained between the output voltage and the output current at a constant input current. It is represented between VCB and IC in constant IE in CB configuration.

Process:

Input Features:

Connect the circuit as shown in the circuit diagram.
Keep the output voltage VCB = 0V by varying VCC.
Varying VEE gradually, note the emitter current IE and the emitter-base voltage (VEE).
The size of the pitch is not fixed because of the non-linear curve. Initially vary VEE in steps of 0.1 V. Once the current begins to increase VEE vary in steps of 1V up to 12V.
Repeat the above procedure (step 3) for VCB = 4V.
Output Features:

Connect the circuit as shown in the circuit diagram.
Keep the emitter current IE = 5mA by varying VEE.
Varying VCC gradually in steps from 1V to 12V and record collector current IC and collector-base voltage (VCB).
Repeat the above procedure (step 3) for IE = 10mA.
Repeat the above procedure (step 3) for IE = 10mA.

Observations:

Input characteristics
VEE (Volts) VCB = 0 V VCB = 4 V
VEB (Volts) IE (mA) VEB (Volts) IE (mA)

Output characteristics
VDC (Volts) IE = 0mA IE = 5 V EI = 10 mA
VCB (Volts) IC (mA) VCB (Volts) IC (mA) VCB (Volts) IC

Graphic:

Trace the input characteristics for different VCB values by taking VEE on the X axis and IE on the Y axis with VCB as the constant parameter.
Trace the output characteristics by taking VCB on the X axis and taking IC on the Y axis with IE as a constant parameter.
Graph calculations:

The parameters h will be calculated from the following formulas:

Input characteristics: To obtain input resistance, look for VEE and IE for a constant VCB in one of the input characteristics.
Input impedance = hib = Ri = VEE / IE (VCB = constant)

Inverse voltage gain = hrb = VEB / VCB (IE = constant)

Output characteristics: To obtain output resistance, look for IC and VCB in a constant IE.
Output = hob = 1 / Ro = IC / VCB (IE = constant)

Forward current gain = hfb = IC / IE (VCB = constant)

Inference:

The input resistance is in the order of tens of ohms since the emitter-base junction is forward biased.
The output resistance is in the order of hundreds of kilo-ohms since the Collector-Base junction is reverse polarized.
The higher the value of VCB, the smaller the voltage cut.
The increase in the value of IB causes saturation of the transistor to small voltages.
Precautions:

When performing the experiment, do not exceed the classifications of the transistor. This may cause damage to the transistor.
Connect the voltmeter and ammeter to the correct polarities as shown in the circuit diagram.
Do not turn on the power supply unless you have checked the circuit connections according to the circuit diagram.
Be sure to select the transistor emitter, base, and collector terminals.
Result:

The input and output characteristics of a transistor in common base configuration are studied.

The parameters h for a transistor in CB configuration are:

The input resistance (hib) __ Ohms.
The reverse voltage transfer ratio (hrb) __.
The Output Input (counter top) __ Mhos.
The win

[ganesh]

A compilation of important assorted transistor simple circuits to build has been included here. Many simple transistor configurations like, rain alarm, delay timer, set reset latch, crystal tester, light sensitive switch and many more have been discussed in this article.

In this compilation of simple transistor circuits (schematics) you will come across many small very important transistor configurations, especially designed and compiled for new budding electronic enthusiasts.

The simple circuits to build (schematics) shown below have very useful applications and are yet easy to build even for new electronic enthusiasts. Let s begin discussing them:

Adjustable DC power supply: A very nice adjustable power supply unit may be built using just a couple of transistors and a few other passive components. The circuit provides good load regulation, its maximum current being not more than 500mA, sufficient for most applications.

Rain Alarm: This circuit is built around just two transistors as the main active components. The configuration is in the form of a standard Darlington pair, which increases its current amplification capacity hugely. Rain drops or water drops falling and bridging the base with the positive supply is enough to trigger the alarm.

Hum free power supply: For many audio amplifier circuits hum pick-ups can become a big nuisance, even proper grounding sometimes are unable to rectify this problem. However, a high-power transistor and a few capacitors when connected as shown can definitely curb this problem and provide the required hum free and ripple free power to the entire circuit.

Set-Reset Latch: This circuit also utilizes a very few components and will faithfully set and reset the relay and the output load according to the input commands. Pressing the upper push switch energizes the circuit and the load, whereas it is deactivated by pressing the lower push button.

Simple Delay Timer: A very simple yet very effective timer circuit can be designed by incorporating just two transistors and other handful of components. Pressing the push ON switch instantly charges the 1000uF capacitor and switching ON the transistors and the relay. Even after releasing the switch the circuit holds on the position until C1 is completely discharged. The time delay is determined by the values of R1 and C1. In the present design it s around 1 minute.

Crystal Tester: Crystals can be quite unfamiliar components especially with the electronic novices. The shown circuit is basically a standard Colpitts oscillator incorporating a crystal to initiate its oscillations. If the connected crystal is a good one, will be indicated through the illuminated bulb, a faulty crystal will keep the lamp shut.

Water Level Warning Indicator: No more peeping and nervous apprehensions with overflowing water tanks. This circuit will produce a nice little buzzing sound well before you tank spills over. Nothing can be as simple as this one.
Keep watching for more of these little giants, I mean simple circuits to build with huge potentials.

[anujr23]

The design of a transistor allows it to function as an amplifier or a switch. This is accomplished by using a small amount of electricity to control a gate on a much larger supply of electricity, much like turning a valve to control a supply of water.

Transistor terminalsTransistors are composed of three parts a base, a collector, and an emitter. The base is the gate controller device for the larger electrical supply. The collector is the larger electrical supply, and the emitter is the outlet for that supply. By sending varying levels of current from the base, the amount of current flowing through the gate from the collector may be regulated. In this way, a very small amount of current may be used to control a large amount of current, as in an amplifier. The same process is used to create the binary code for the digital processors but in this case a voltage threshold of five volts is needed to open the collector gate. In this way, the transistor is being used as a switch with a binary function: five volts ON, less than five volts OFF.

TransistorsSemi-conductive materials are what make the transistor possible. Most people are familiar with electrically conductive and non-conductive materials. Metals are typically thought of as being conductive. Materials such as wood, plastics, glass and ceramics are non-conductive, or insulators. In the late 1940 s a team of scientists working at Bell Labs in New Jersey, discovered how to take certain types of crystals and use them as electronic control devices by exploiting their semi-conductive properties.Most non-metallic crystalline structures would typically be considered insulators. But by forcing crystals of germanium or silicon to grow with impurities such as boron or phosphorus, the crystals gain entirely different electrical conductive properties. By sandwiching this material between two conductive plates (the emitter and the collector), a transistor is made. By applying current to the semi-conductive material (base), electrons gather until an effectual conduit is formed allowing electricity to pass The scientists that were responsible for the invention of the transistor were John Bardeen, Walter Brattain, and William Shockley. Their Patent was called: Three Electrode Circuit Element Utilizing Semiconductive Materials.

[hanamaraddi1]

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[sailesh]

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[jaswalsaurabh]

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