Hey Prabha,
Generally Mathematics, Science & English are considered to be compulsory subjects to apply for most of the polytechnic courses. You can find more details regarding the same in the following link:
https://engineering.careers360.com/articles/polytechnic
However, being a PCB student, you can definitely try for diploma courses in biological science field. Also, you can take admission in diploma in computer science if that is something that interests you.
All that said, it is highly recommended that you take an admission in any degree course as that will be much more rewarding. The followings are some of the options you may try out.
All the best.
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