Hello,

According to your query the most important subjects for Gate in Instrumentation are:

• Control Systems 
• Digital Electronics
• Measurements
• Process Control and Transducers
• Optical Electronics

Hence these are some of the important topics which can cover the major portion of the paper.

ThankYou!

All the Best!

For Gate 2020

Regards!

Shikhar Singh Chauhan

To qualify for GATE 2020 in the stream of instumentation you need to focus on main subjects like

• Electrical Circuits
• Control Systems
• Signals and systems
• Analog and Digital Electronics
• Sensors and industrial Instrumentation
• and common subject Engineering mathematics

You have focus on these subjects on long term will help you to get good score in GATE. All the Best.