Although these are three completely separate charges, they are often very closely related. This is because any one of these offenses is typically (though not necessarily) carried out simultaneously with the others.
Let's take an example. Suppose that Rich points a loaded gun at Mary and threatens to shoot her if she doesn't comply with his demands. This type of generic situation takes place all the time.
Given these facts, Rich is guilty of Penal Code 417 PC, California's brandishing a weapon law, California Penal Code 245 PC assault with a deadly weapon, and California Penal Code 422 criminal threats. And, depending on Rich's actual demands, he is likely guilty of additional offenses as well.
These three offenses — Penal Code 417 PC, California's brandishing a weapon law, California Penal Code 245 PC assault with a deadly weapon, and California Penal Code 422 criminal threats — all involve similar allegations. Brandishing a weapon involves exhibiting a weapon in a threatening manner. Assault with a deadly weapon involves an unlawful intent to commit a violent injury upon another person using a deadly weapon. And criminal threats involve a threat of immediate harm that places the recipient in fear.
Because these crimes are so closely connected, what seems like only one criminal act can actually trigger a host of criminal charges. (Read our article, "Assault with a deadly weapon v. Assault with a firearm in California.")