DC-DC Converters and Battery Characteristics
DC-DC Converter Analysis
Boost Converter
A boost DC-DC converter switches at 100 kHz. The input is +12 V and the duty ratio of the transistor is 75%. The input inductor is 25 μH, and the output capacitor is 100 μF. If the load draws 50 W, the output voltage is found to be 48 V.
Output Voltage Calculation
What is the output voltage for a 10 W load? If L > Lcrit and C > Ccrit, then Vout/Vin = 1/D2. With a 50 W load, Vout = 48 V. This gives D2 = 0.25, so it would be continuous mode. For a 10 W
Read MorePneumatic Compressors and Valves: Types & Applications
Pneumatic Compressors
Piston Compressor
This compressor sucks in air at atmospheric pressure and then compresses it. It consists of intake and exhaust valves, a piston, and a connecting rod-crank mechanism.
Admission:
The shaft rotates clockwise. The crank pulls the piston down, and the intake valve lets air in 10º after Top Dead Center (TDC) until Bottom Dead Center (BDC).
Escape:
At BDC, the intake valve closes, and as the piston ascends, it compresses the air. Under pressure, the exhaust valve opens
Read MoreEnergy and Its Transformations: A Comprehensive Guide
Energy and Its Transformations
Energy Sources and Transformations
We obtain energy from primary energy sources and transform it daily. We can use energy in its primary form (e.g., wind’s kinetic energy to move a boat). We distinguish between primary, intermediate, and useful energies. For example, an engine transforms the chemical energy of petrol (primary) into heat (intermediate), which can then be transformed into kinetic energy (useful). The most common intermediate energy is electricity.
Types
Read MoreIntroduction to Geographic Information Systems (GIS)
Vector and Raster Data in GIS
The digital GIS representations of geographic features are called vector and raster data. Vector data are designed for discrete objects and are represented with pairs of x, y coordinates.
- Point features have a single pair of coordinates. Examples include a tree or an electric pole.
- Lines are represented with a start node and a stop node, and usually several vertices between these nodes, all having defined positions (pairs of x, y coordinates). Examples include roads or
Petroleum Distillation and Gasoline Properties
REDUCED PRESSURE DISTILLATION
Distillation is a process designed to separate liquids by boiling point. After fractional distillation or topping, a material called petroleum spirit is obtained and must be further distilled for use. The problem is that if it is distilled in the same way as crude oil, its high boiling point would cause much of the material to evaporate or burn. The decomposition temperature of the material is less than the boiling point. At 350 °C the carbon chains begin to decompose.
Read MoreTransformers: Principles, Connections, and Applications
Transformers
Schedule Index
The process for determining the rate schedule is as follows:
- For single-phase transformers, represent the primary winding so that terminal A is at the top of the diagram (coinciding with the number 12 of an imaginary clock placed overlapping the vector diagram).
- Represent the secondary winding, noting that primary and secondary windings located in the same column produce in-phase FEMs (homologous terminals).
- Overlap both diagrams. The schedule is the angle formed by two vectors: