Saturday, 24 July 2021

20 watt LED tube light AC or DC

 It is AC LED tube light bulb.

Because in AC LED tube light, there is small circuit is fitted inside LED tube light. 

As we know that all bulb and tube light is glow, when it gets directs current its means DC current or DC voltage.

But in our 230V AC (Alternate Current) is supplied from power house.

So therefore when AC current or voltage come in LED or tube light its rectifies into DC current or voltage with the help of rectifier circuit which present in the LED.

   So simply when AC is input Rectifier circuits presents inside LED bulb which convert AC to DC.

Write the 10 points of transistor

 1) Transistor is a semiconductor device.

2) Transistor can be used for both conduct and insulate electric current and voltage.

3) Transistor basically used as a switch and an amplifier.

4) There is two types of BJT (Bipolar Junction Transistor) 

       i) P-N-P Transistor

       ii) N-P-N Transistor

5) BJT Transistor has three terminal there are Base, Emitter and Collector.

6) There are three types of Transistor i) BJT (Bipolar Junction Transistor)

                                                            ii) FET (Field Effect Transistor)

                                                            iii) IGBT ( Insulated Gate Bipolar Transistor)

7) In BJT Transistor there are three types of configuration i) Common Base (CB)

                                                                                              ii) Common Collector (CC)

                                                                                              iii) Common Emitter (CE)

8) The advantage of Transistor is i) Low cost and small in size.

                                                      ii) Low operating voltage.

                                                      iii) No power consumption.

                                                      iv) Fast switching.

9) The limitation of Transistor is : Transistor lack higher mobility.

10) The limitation of transistor is : The Transistor effected by cosmic rays and radiation.


Friday, 23 July 2021

How many SCRs uses in full wave controlled rectifier with midpoint (Centertaped) ?

 In full wave controlled rectifier with midpoint (Centertaped) there is only 2 SCRs is required.

Deepak Joshi is a science student or no

 As you know the life of Arts, Commerce and science students. Science students life, its full with stress and hard working study life.

As you know that Science student always do their study. they have not any extra time to go any way for enjoying. Because science study is very much costly and tough.

But as you know about commerce student life, it is less pressure. Because Commerce students have only theory work and not practical work.

As Commerce students life = As Arts students life.

But as we see depth in science students life, it has not only pressure of theory but it has also pressure of practical writing and practical exam.

So from my point of view, Science students have not much time to do like tik tok videos.



Give reason why ultrasonic sound waves are sent from ships towards the seabed

 First of all we know that, what is ultrasonic sound :- The sound having frequency above human audible range are called as ultrasonic sound or supersonic sound.

We human can only heard sound in range from 20 Hz To 20 KHz.

But in case of ultrasonic sound it is above 20 KHz range.

For determine the depth of sea, therefore ultrasonic sound waves are sent from ships toward the seabed.

Sunday, 18 July 2021

What is source wave determined?

 1)The source waves sends outs its waves in all possible directions.

 2) Source wave is also known by primary source wave.

3) Secondary source wave is formed by primary source wave.

Advantage of secondary wavelets for Huygens principle

 1) Its sends out secondary waves only in forward direction.

2) Secondary wave is effective only at the points where it touches the envelope.

3) Secondary source is situated on a wave front.

Firing potential of SCR is applied to which terminal

 As we know that SCR has three terminal like : i)  Anode (A) 

                                                                            ii) Cathode (K)

                                                                            iii) Gate  (G)

To turn ON SCR there is only two ways : 1) Increase the forward voltage beyond the break over voltage.

                                                                   2) By giving positive triggering gate pulse to the SCR.


The firing potential of SCR is applied to the Gate terminal of the SCR.

Thursday, 1 July 2021

Light Dimmer by using Triac (Project)

Title: Light Dimmer by using Triac.

Objectives: Dimmers are device connected to a light fixture and used to lower the brightness of light. By changing the voltage waveform applied to lower the intensity of light output.

Leaning Outcomes: i) We learn how light brightness actually controlled by using light dimmer.

 ii) We learn how dimmer circuit controlled light brightness from lower to higher brightness level.

iii) And one more one thing is that, we actually learn its working and how trice is used here for controlling it's light-brightness.

Prior Concept: Working of light dimmer circuit by using Triac.

Light Dimmer Circuit Using Triac


The Circuit shows the RC phase shift network and DIAC Controlled TRIAC for the light dimming application. The voltage applied to the gate terminal of the triac is varied by the RC arrangement involving the Resistor R3 and the capacitor C3. When the device is in off state, the rate of change or rises of voltage is limited by the series R4-C1 network that is connected across the TRIAC.

Once the input voltage if applied from the 230V power source, the capacitor C1 and C2 start charging at the rate determined by the variable resistor R2. Once the voltage across the capacitor C3 exceeds the breakdown voltage of the DIAC, it gets triggered and the DIAC start conducting and this will discharge the capacitor C3 and the gate pulse is given to the Triac.

The gate pulse turnss ON the TRIAC and the current starts flowing through the lamp. By varying the variable Resistance VRI, the rate of charging of the capacitor also gets varied, which in turn varies the voltage rate, at which the TRIAC gets triggered in both the positive and negative half cycles.

The voltage is applied to half of the AC cycle, then the light bulb will appear with less intensity when it gets the full AC voltage. Because it gets the low power to heat the filament. These light dimmer use the brightness VRI knob to control at what point each cycle to switch the light ON and OFF.

Prior concept: The basic circuit of light dimmer using TRIACis shown in the given figure and this circuit depends on phase control. The variable Resistor VRI plays as a main controller in the light dimmer circuit.

In this light dimmer circuit without any change DIAC, we can be replaced by the BC148 transistor when the transistor is used instead of DIAC, then the base terminal of the transistor not connected and remaining terminals like emitter and collector are connected without the help of polarity.

Conclusion: In light dimmer circuit by using triac we fully controlled brightness level of the light bulb according to our requirement.



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