An arrest warrant is case filed by the district attorney and then a judge approves the issuance of an arrest or "A" warrant for the charged person. An "A" warrant mandates law enforcement to perform due diligence, that is to make an effort to find the wanted person. This is because the wanted person has not yet been arraigned, formerly charged in court, and is entitled to a speedy trial. So the responsibility is on law enforcement to deliver that person to court.
A "B" or bench warrant is simply issued by the court when a defendant fails to appear in court as ordered. This can happen any time after arraignment and during the entire judicial process. No due diligence is imposed upon law enforcement for "B" warrants. All of the above applies to both felonies and misdemeanors.

