Electronic Components and Bipolar Junction Transistor Configurations, Lecture notes of Object Oriented Programming

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ABV-Indian Institute of Information Technology &

Management, Gwalior, India

Dr. Somesh Kumar, Ph.D.

Assistant Professor

List of Basic Electronic Components

 PCB (Printed Circuit Board)

 Breadboard

 Bipolar Junction Transistor (BJT)

 Resistor

 1N4007 Diode

 LED

 Thermistor

 Jumper Wires

 Potentiometer

 Voltage Regulator (7805)

 USB Connector

 Buzzer

 555 Timer IC

 PIR Sensor Module

 7 Segment Display

 Relay

 IR Sensor Module

 Arduino Uno

 ESP8266 Module

 HC 05 Bluetooth Module

 Rasberry Pi

PCB (Printed Circuit Board)

 General Purpose PCB  Cu Clad PCB  The plain circuit boards are a type of printed circuit boards which are plain and uniform in shape.  The circuits are formed of the thin layer of the conducting material mainly copper and individual components are placed with the soldering iron.

Breadboard

Bipolar Junction Transistor (BJT)

 The basic transistor principle is that the voltage between two terminals controls the current through the third terminal.  Current in the transistor is due to the flow of both electrons and holes, hence the name bipolar. NPN BJT with forward-biased E–B junction and reverse-biased B–C junction

Bipolar Junction Transistor (BJT)

 Bipolar Transistor Configurations As the Bipolar Transistor is a three terminal device, there are basically three possible ways to connect it within an electronic circuit with one terminal being common to both the input and output. Each method of connection responding differently to its input signal within a circuit as the static characteristics of the transistor vary with each circuit arrangement.  Common Base Configuration – has Voltage Gain but no Current Gain.  Common Emitter Configuration – has both Current and Voltage Gain.  Common Collector Configuration – has Current Gain but no Voltage Gain. Common Base Transistor Circuit Common Emitter (CE) Configuration Common Collector (CC) Configuration

Bipolar Junction Transistor (BJT)

Common Base Transistor Circuit  The input current flowing into the emitter is quite large as its the sum of both the base current and collector current respectively therefore, the collector current output is less than the emitter current input resulting in a current gain for this type of circuit of “1” (unity) or less,  common base configuration “attenuates” the input signal.  This type of amplifier configuration is a non-inverting voltage amplifier circuit, in that the signal voltages Vin and Vout are “in-phase”.  This type of transistor arrangement is not very common due to its unusually high voltage gain characteristics. Ic/Ie is the current gain, alpha ( α ) and RL/Rin is the resistance gain.

Bipolar Junction Transistor (BJT)

Common Collector (CC) Configuration  In the Common Collector or grounded collector configuration, the collector is now common through the supply.  The input signal is connected directly to the base, while the output is taken from the emitter load as shown.  This type of configuration is commonly known as a Voltage Follower or Emitter Follower circuit.  This type of bipolar transistor configuration is a non-inverting circuit in that the signal voltages of Vin and Vout are “in-phase”.  It has a voltage gain that is always less than “1” (unity).

Bipolar Junction Transistor (BJT)

Regions of operation: Bipolar transistors have four distinct regions of operation, defined by BJT junction biases.

 Forward-active (or simply active): The base–emitter junction is forward biased and the base– collector junction is reverse biased. Most bipolar transistors are designed to afford the greatest common-emitter current gain, βF, in forward-active mode. If this is the case, the collector–emitter current is approximately proportional to the base current, but many times larger, for small base current variations.  Reverse-active (or inverse-active or inverted): By reversing the biasing conditions of the forward-active region, a bipolar transistor goes into reverse-active mode. In this mode, the emitter and collector regions switch roles  Saturation: With both junctions forward-biased, a BJT is in saturation mode and facilitates high current conduction from the emitter to the collector (or the other direction in the case of NPN, with negatively charged carriers flowing from emitter to collector). This mode corresponds to a logical "on", or a closed switch.  Cut-off: In cut-off, biasing conditions opposite of saturation (both junctions reverse biased) are present. There is very little current, which corresponds to a logical "off", or an open switch. No current

Resistor

If resistor has no fourth tolerance band then the default tolerance would be at 20%.

1N4007 – PN Junction Diode

Operating regions:

1. Zero Bias – No external voltage potential is applied to the PN junction diode.
2. Reverse Bias – The voltage potential is connected negative, (-ve) to the P-type material and positive, (+ve) to the N-type material across the diode which has the effect of Increasing the PN junction diode’s width.
3. Forward Bias – The voltage potential is connected positive, (+ve) to the P-type material and negative, (-ve) to the N-type material across the diode which has the effect of Decreasing the PN junction diodes width. Reduction in the Depletion Layer due to Forward Bias Increase in the Depletion Layer due to Reverse Bias Zero Bias

Light Emitting Diode (LED)

 A light-emitting diode is a semiconductor light source that emits light when current flows through it.  Electrons in the semiconductor recombine with electron holes, releasing energy in the form of photons (Electroluminescence).  Electrons in the semiconductor recombine with electron holes, releasing energy in the form of photons.  The color of the light (corresponding to the energy of the photons) is determined by the energy required for electrons to cross the band gap of the semiconductor.  OLED uses organic material, in the form on carbon, to provide a natural light source to light the display. This allows for OLED screens to be bigger, lighter, and retain consistent color from even the widest viewing angles. OLED

Thermistor

 Thermistors are Temperature Dependent Resistors i.e. the resistance of the thermistor varies according to the ambient temperature.  PTC Thermistor; Positive Temperature Coefficient and NTC Thermistor; Negative Temperature Coefficient  In PTC resistance is directly proportional to temperature and in NTC resistance is inversely proportional to temperature.  Thermistors act as a passive component in a circuit.  We can measure the resistance of a thermistor using an ohmmeter.  How much the resistance changes depends on the type of material used in the thermistor.  The typical size of a thermistor is 0.125mm to 1.5mm. Commercially available thermistors have nominal values of 1K, 2K, 10K, 20K, 100K, etc. This value indicates the resistance value at a temperature of 25oC. Some of the most common uses of thermistors include:  Digital thermometers (thermostats)  Automotive applications (to measure oil and coolant temperatures in cars & trucks)  Household appliances (like microwaves, fridges, and ovens)  Circuit protection (i.e. surge protection)  Rechargeable batteries (ensure the correct battery temperature is maintained)  Useful in many basic electronic circuits (e.g. as part of a beginner Arduino starter kit)  Temperature compensation (i.e. maintain resistance to compensate for effects caused by changes in temperature in another part of the circuit)

Potentiometer

 A potentiometer (also known as a pot or potmeter) is defined as a 3 terminal variable resistor in which the resistance is manually varied to control the flow of electric current. A potentiometer acts as an adjustable voltage divider.  If only two terminals are used, one end and the wiper, it act as a variable resistor or rheostat.