For admission to Delhi University (DU), a recent character certificate is typically required, especially for students with a gap after completing their 12th grade. This certificate is generally valid for six months.

Regarding a character certificate signed by a doctor, it's important to note that not all professionals are recognized as authorities for issuing such certificates for university admissions. Delhi University typically requires the certificate to be issued by your previous educational institution or a recognized authority like a gazetted officer. Therefore, a certificate signed by a doctor may not be accepted unless the doctor holds a position as a Gazetted officer.