Hello

Yes, sure you can join the ISRO having diploma degree in electrical. There are many posts available in ISRO for diploma holders in CSE like---

Technical Assistant

Library Assistant

Scientific Assistant

The no. of vacancies use to be very less. So it becomes a very tough competition.

But, I would suggest you to pursue B Tech ,if you want to apply for scientist---

Junior scientists

Senior scientists-After having 8-10 years experience

And they recruits first class students that is high profile students having board toppers as well as university Topper.

Hope it helps