AC Electrical Machines: Synchronous Motors
AC Electrical Machines
Synchronous Motors and Generators
AC electrical machines are classified into two main types:
- Synchronous motors and generators: The coil inductor current is supplied by a separate source of direct current (DC).
- Induction motors: The inductor winding current is provided by magnetic induction.
Differences Between AC and DC Machines
The location of the coils and inductors differs depending on the type of machine. In an AC machine, there is no electrical connection between the rotor
Read MoreRadiation Detectors: Geiger Counters, Cloud Chambers, and More
Radiation Detectors: A Detailed Look
Geiger Counter
A Geiger counter consists of a central wire inside a hollow metal cylinder filled with gas at low pressure. An electrical voltage is applied between the cylinder and the wire, making the wire more positive than the cylinder. When radiation enters the tube and ionizes an atom in the gas, the released electron is attracted towards the positively charged central wire.
As the electrons accelerate toward the wire, they collide with other atoms, releasing
Read MoreTouchscreen Technologies: Ultrasonic, Near Field, and Standards
Touchscreen Technologies and Display Standards
Ultrasonic Touchscreen Technology
Used technology: Ultrasonic transducers generate surface waves transmitted through the glass surface and received by sensors on the opposite side. A pointer touching the screen absorbs some acoustic wave energy. The receiver measures changes in the received acoustic wave’s amplitude to detect the pointer’s position.
Advantages
- Total light transmission
- Protection through a graphical display
- Ability to detect the depth of the
Metal Cutting Principles: Forces, Tool Wear, and Operations
Cutting Forces and Temperatures
The chip consists of a plastically deformed workpiece. The plastic deformation of the cut layer occurs under the action of a force which must be greater than the resistance of the metal to deformation and destruction.
Temperature: Heat is released during the cutting process as the cut layer is deformed and frictional processes take place in the cutting area. Almost all mechanical work (about 99%) to cut the chip is converted into heat, so the temperature during cutting
Read MoreMetal Forming and Machining Techniques
Metal Forming Techniques
When you want to obtain metal parts of complex geometry, melting and forming processes are used. This involves pouring the molten material into a mold containing the hollow shape of the object you want to create, and then letting it cool.
Deformation Techniques
These techniques consist of subjecting the material to continuous deformation until it reaches the desired size and shape. Examples include:
- Forging: A process by which a material, heated to an optimum temperature, undergoes
Semiconductors: Intrinsic, N-Type, P-Type, and PN Junctions Explained
Semiconductors: Intrinsic, N-Type, and P-Type
Intrinsic semiconductors are semiconductors with no impurities. They are characterized by having 4 electrons in the last layer of atoms and form a stable structure, binding to the neighboring atoms with covalent bonds, sharing 4 pairs of electrons.
Semiconductor N-Type
An N-type semiconductor is extrinsic, i.e., containing a number of impurities. If some atoms with 5 electrons in their last layer are added to a pure semiconductor (intrinsic), these atoms
Read More