• Most of the Public Sector Undertakings shortlist candidates on the basis of their GATE scores followed by an interview. Ex. BHEL, ONGC, BPCL, HPCL, DMRC etc. Hence, writing GATE gives more options for core government jobs.
• Apart from that, several other PSU's still conduct their own exams. Ex. SAIL, CIL, BSNL, ISRO etc. The exams for these PSUs are conducted every year between March and September.
• For central government, ESE(Engineering Services Exam) is conducted every year by UPSC in various disciplines of engineering such as Electrical, Mechanical, Civil and E&T.

Hi Jigyasu, 

Your best choices are ISRO and BEL. These are only two companies that take ECE students in relatively huge numbers (both take in almost 80 people every year). One good thing is they have their own exam. So even if you screw up your GATE, you don't have to worry.

You can write the NET exam and join as a JRF in any of the prestigious research labs of CSIR, IITs, NITs, IIST etc. This exam is held twice a year(June/July and Dec/Jan). This, if you are interested in research.

All the best!