It is called an rpm (revolution per minute) to the unit that is used to express the angular velocity. It is the number of complete turns a body gives around an axis.

Although there are infinity tips as manufacturers or type of use, these are the most commonly tips used in the electronics industry, hardware or electricity.

1. Slot: Characterized by its flat and elongated tip.

2. Phillips: It may be the most used, its tip is shaped like a four-pointed star. Also called commonly screwdriver

3. Pozidriv: Like the previous model, but with a twist. Inside it has 4 slots in a star more.

4. Torx: Widely used in vehicles, its shape is a star with 6 points.

5. Security Torx: Same as above, but inside has a pin.

6. Hex: Point-shaped or hexagon Allen calls. Such tips are distinguished from the rest because they are able to withstand higher torque strength.

VDC would be the abbreviation for Volt Direct Current which translated would volts direct current. The idea of ??this type is unidirectional current to the load. Direct current is normally produced by batteries, thermocouples, solar cells and a dynamo electric machine type. The direct current can flow in conductors such as wires, but may also flow through semiconductors, insulators ... In the image: 1 - current per pulse 2 - Direct Current (DC) 3 - Alternating Current (AC) 4 - Variable Current