Section 249-A of Cr.PC has very importance because it gives the power to the court of magistrate to acquit accused.
This section is applicable only on Magistrate class. The Schedule II of Cr.P has a tabular form. You can easily check which section of PPC is dealt by which court.
Usually all those offences whose punishment is less then 3 years or 7 years (in case magistrate S 30). Then applicant can file application under section 249-A of Cr.PC.
Again this Application under section 249-A of Cr.PC has two ingredients. That is either charge is groundless or there is no probability of conviction.
If any one of these ground exist then you can file Application under section 249-A of Cr.PC and can acquit accuse from jail.
At any stage
Section 249-A also authorizes court to acquit accuse at any stage whether charge is framed or not, evidence is recorded or not, before judgment is pronounced.