IIT JEE and NEET Physics @ Venkats Academy IIT-JEE and NEET Physics

A logic gate is a particular electronic circuit to execute a certain logic that we are interested.The kind of logic that you want to execute depends on the requirement.

For example assure that you’re having a fan that has to be switched on.Let it has two switches available at the two sides of a room.If you want the fan to be switched on when at least one of that switches is on, the kind of the logic that you shall execute is similar to OR gate logic.

And if you would like to have your fan to be switch on only when both the switches are on, then the kind of the logic that you want to execute is called and the gate logic. Whenever the switches on if you want the fan to be switched off and vice versa, then the kind of the logic that you are looking for is actually a NOT gate.All this logic gates works basing an algebra called Boolean algebra.

OR gate works basing on the union logic,AND gate basing on intersection logic and NOT gate basing on negation logic of mathematics.

OR gate

This works basing on the union function of the mathematics. You might know that if there are two functions and we will write the member in the union function when it exists at least in any one of the functions.

AND GATE

This works basing on intersection function of the mathematics.The output will be on when only both the inputs are on in this kind of the gate. The NOT gate just reverse the input that is given and make it as the output.

NOT gate

NOT gate is a negation gate. Whatever the input that is given,IT will be just reverse that INPUT. That means if the input is ON, the output will be OFF and vice versa.

This three gates are called BASIC gates which are going to be useful to execute basic logic that we wish to execute in any electronic circuit. Anyway there are further hybrid gates available in the logic gates called NOR and NAND Gates.

NOR gate

NOR gate is the combination of OR gate and NOT gate. The results of this gate is the negation results of the OR gate. The truth table of the gate is shown below. This gate is also called as a universal gate because we can get all the basic gates with this gate.

NAND GATE

NAND gate is a combination of NOT gate and AND gate. The output of this gate is reciprocal of the AND gate. This gate is also called as a universal gate. The truth table of the gate is shown below.

PN Junction Diode in Forward Bias and Reverse Bias
Solving Problems on the Concept of P N Junction Diode

P N Junction Diode as Half Wave Rectifier

P N Junction Diode as Full Wave Rectifier

Zener diode as Voltage Regulator

Working of Transistor in Common Base Configuration

Transistor in Common Emitter Configuration

Transistor as Feedback Oscillator

Generally a transistor can act like an amplifier and when you give a consistent input, it will amplify and give a consistent output. But here we are looking for a kind of amplifier which can give a consistent output without even giving a continuous input. This kind of the feet can be achieved by taking a portion of the output and connecting it back to the input transistor.This kind of the circuit is called feedback circuit. The very purpose of the feedback circuit is to pass the portion of the output that is taken back to the input without any serious loso at the output level.This can be achieved by the concept of the mutual inductance as well as the LCR circuit network of alternate currents.

The LCR circuit is being designed in such a way that, for a certain frequency of the alternate current their opposition to the flow of the current which is being called as an impedance is minimum and hence they are able to pass the best possible current to the circuit back and it is the most effective way of working.

Therefore there is no loss of the output that has to be pass it to the input and the consistent output is automatically amplified with the consistent supply of the feedback circuit.

The LCR circuit consists of a inductor, capacitor and resister. Though they are connected in series the flow of the current is going to have different phases when alternate current is passing through them. We know that alternate current will go in phase both in terms of voltage and current when it is passing through a resister. In the case of a resister current and voltage go hand-in-hand such that between them there is no phase difference in an alternate current is passing through it.

When the alternate current is passing through a inductor voltage leads by 90° when compared with the current. When alternate current is passing through a capacitor voltage lacks by 90°. Hence it referred as inductor and capacitor are having a phase difference of 180°. The opposition to the flow of the current by the inductor is called inductive reactance and by the capacitor is called capacity reactance. They are having a phase difference of 180° between them. The resultant of this is perpendicular to resistance and the total opposition of all these things together is called impedance. The impedance of the circuit will be minimum when capacity reactance is equal to the inductive reactance,so that both of them cancels each other and the impedance is equal to the resistance of the resister itself.