Prerna Gupta

8 Questions 3 Answers 0 Followers

Questions related from Prerna Gupta

Why patch antennas are used instead of planar dipole antenna?

As much as I know the major advantage of patch antenna over dipole antenna is it's directivity. So if the planar dipole antenna can achieve the same directivity then why we use patch antenna? Are...

17 June 2022 7,678 5 View

Why two wires are used in railway overhead equipment?

While studying railway overhead equipment I seen two different images of catenary system. After searching on internet I found that both catenary and contact wires carry same voltage and connected...

12 May 2022 1,565 1 View

Why we use various layers in OLED (ETL,EIL,HTL,HIL)? How they increase efficiency OLED device?

Currently, I am studying the working of OLED devices! The device can work with just three layers which are Anode, Cathode and Emission layers. I know the fact that the work function is an...

12 January 2022 7,854 3 View

How sound waves travel through a barrier?

How do sound waves travel through a barrier? A sound wave is the result of compression and rarefaction of gases. This pressure difference makes the air molecules oscillate. [Fig 1] When sound...

11 January 2022 5,781 3 View

Why a quadruped uses 3 degrees of freedom(dof) for each leg instead of 2dof. What are the disadvantages of using 2dof for each leg?

A quadruped robot has four legs. Each legs has 3 degrees of freedom i.e 3 joints. But the quadruped robot can also move with 2 joints on each leg. What are the disadvantages of using 2 joints...

10 December 2021 265 2 View

Why there are different energy level in Organic layer of OLED device?

Currently, I am studying the working on the OLED screens in detail. I have come across various layers of systems, for example, HIL, HTL, ETL, EIL and EML. I have studied that each layer has...

13 November 2021 7,188 1 View

Why we use anode and cathode in OLED? Why cant directly connect organic layer to power supply in OLED? ?

Currently, I am studying the working principle and mechanism of an OLED display. So my question is why we required the cathode and anode material in OLED? why we can't connect the organic layers...

12 November 2021 2,650 3 View

Why do we need an emissive layer in OLED? why we can not directly connect Hole Transfer Layer to Electron Transfer Layer just like in LED?

Currently, I am studying the working Principle of the OLED screen panels. Why do we use the emissive layer in between the Electron & Hole transfer layer in OLED devices? Why do we did not...

08 November 2021 9,249 3 View