Fixed Bias Transistor Circuits

Few Points: Two batteries vBB and VCC used VBB gives potential to base terminal through RB. VCC  supplies power to the collector through RC. Base resistance RB  of the order of hundred kilo ohm Collector resistance RC of the order of kilo ohm. Aim: To find dc base current IB, IC, VCE and IE  For this purpose, we are going to convert  above circuit in electrical equivalent circuit. For making calculation easy, we divide this circuit in two part, (i) Input Part and (ii) Output Part (I)  Input Part:Applying KVL:We get, VBB = IBRB + VBEOr  IB = ( VBB – VBE )/ RBFor Silicon Transistor, VBE = 0.7 V and For Ge Transistor, VBE = 0.3 V (ii) Output Part: Applying KVL...

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Posted in: Electronics,transistor

Biasing of Transistor:

Need of Biasing: The proper flow of zero signal collector current and the maintenance of proper collector emitter voltage during the passage of signal is called the transistor biasing. It is essential for faithful amplification. If the transistor is not biased properly, It would be Work inefficiently  Produce distortion in the output signal. Keep in Mind: Input side should be in Forward Biased Output side should be in Reverse Biased Base Resistance RB >>RC There are some transistor biasing circuits:Fixed Bias Potential Divider Bias Two Supply Emitter Bias Emitter – Feedback Bias Collector Feedback Bias Collector – and Emitter – Feedback Bias ...

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Posted in: Electronics,transistor

Troubleshooting of a Transistor circuit

Troubleshooting  a circuit:1.       Measure the Vce. 2.       When troubles come, they are usually big troubles like shorts or opens. 3.       Short: when  devices damaged, solder splashes across resistors. 4.       Open: when components burn out. 5.       These troubles produce large changes in voltages and currents  Welcome to S2P Group. For more information. connect to study2placement.blogspot.comCause of these troubles:1.       Trouble in the power supply2.       An open lead between the power supply and the...

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Posted in: Electronics

Projects Based on C++

There are some useful projects for Computer Science students: Shop Bill Based on C++ Snake Game Based on C++ Address Book Based on C++ Company Details Based on C++ Diabetes Detection Based on C++ Railway Reservation Based on C++ Alternative Railway Reservation Based on C++...

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Posted in: cpp

Electronic mosquito repeller

Here is the circuit diagram of an ultrasonic mosquito repeller.The circuit is based on the theory that insects like mosquito can be repelled by using sound frequencies in the ultrasonic (above 20KHz) range.The circuit is nothing but a PLL IC CMOS 4047 wired as an oscillator working at 22KHz.A complementary symmetry amplifier consisting of four transistor is used to amplify the sound.The piezo buzzer converts the output of amplifier to ultrasonic sound that can be heard by the insects. Circuit diagram : Main Parts Used: IC CD4047 ( a Phased Lock Loop) - 1 4 Transistor ( 2 NPN (SL100) and 2 PNP (SK100)) Capacitors ( 4.7 nF, 22uF 16V) 10K Potentiometer - 1 Welcome to S2P Group. For more details: www.study2placement.blogspot.com Note Assemble...

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Posted in: Electronics,Mosquito Repellent,PLL

How does the Timer 555 work

Block diagram for the 555 timer is given in fig. Main Parts of 555 Timer: Two comparators (simply Op-Amp) An R-S Flip-flop Two Transistors A Resistive networks consisting three equal resistors and acts as a voltage divider Working: In most applications, the control pin is not used, so that the control voltage equals +2Vcc/3 . Output of comparator 1 is applied to set (S) input of the flip-flop. Whenever the threshold voltage exceeds the control voltage, comparator 1 will set the flip-flop and its output is high. A high output from the flip-flop saturates the discharge ttransistor and discharge the capacitor connected externally to pin 7. The complementary signal out of the flip-flop goes to pin 3, the oputput. The output available at pin...

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Posted in: 555,Electronics

How a Capacitor Works

An electrical capacitor is made of two small conductive plates separated by what is called a dielectric, which effectively insulates the two plates and stops any current from being transferred between the plates themselves. Instead, the two plates are connected through a circuit. When the circuit is taken out, the plates store the electrical current because it can't flow between the plates. The way a capacitor works is like a water storage tank with a shut-off valve if it gets too full. As electrical current enters the capacitor, the capacitor lets it pass through unaffected. However, the more current flows into the capacitor, the quicker it "fills." This then triggers the capacitor's shut-off mechanism, preventing electrical current from...

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Posted in: Electronics