HVAC full form in electrical

What is the full form of HVAC?

  • High Voltage Alternating Current

What does HVAC mean?

Alternating current call as AC is an electrical current which periodically reverses direction in contrast to direct current which flows only one direction. These currents typically alternate at higher frequencies than those used in power transmission so HVAC is widely used in the transmission and distribution system to reduce electrical losses.

What is converter

Definitions:

The use of the word converter in power electronics which is often used as describing several unrelated pieces of equipment or performing a different function has added to this confusing matter, A converter has a lot of meaning but often time you can really understand what it really meant. A converter converts the voltage of an electrical device, usually alternating current (AC) to direct current (DC). It changes the voltage of an electrical power source and it is usually combined with other components to create a power supply. A converter converts AC to DC, detect amplitude modulated radio signals, supply polarized voltage for welding. 

Types:

The basic difference between various types of converters is that they vary in their nature and the devices they support.
  • Analog to digital converter (ADC): This type of converter is a device that converts the input analog voltage to a digital number proportional to the magnitude of the voltage or current form. Some non-electronic or partially electronic device, like rotary encoder, can be considered as ADCs.
  • Digital to analog converter (DAC): It is a device that converts a digital code to an analog signal, DAC are found in CD players, digital music players and PC sound cards.
  • Digital to digital converter (DDC): It is a device which converts one type of digital data to another type of digital data.
Advantages of the converter:
  • Faster dynamic response.
  • Highly reliable.
  • Highly efficient.
  • Negligible maintenance.
  • Very small size.
Disadvantages of a converter:
  • Poor current overload capacity.
  • Low power factor.
  • The good quality automatic regulators are more expensive than other types of mechanical regulators.

Difference between inverter and converter

The converter has a lot of meaning but often times you can really understand what it really meant. For example in electronics, we have understood easily language that the voltage converter is a device which converts AC power to DC power. It changes the voltage of electrical power source and is usually combined with other components to create power supply while in the inverter is defined as an electrical device that converts direct current to alternating current, the converted AC can be at any required voltage and frequency with the use of appropriate transformers switching and control circuits.

The main difference between inverter and converter is given below:
  • The inverter is an electrical device that converts the voltage from direct current to alternating current while in Converter is an electrical device that converts the voltage from alternating current to direct current.
  • There are different types of inverter like square wave inverter, Quasi-wave or modified square wave inverter pure sine wave inverter wheres converter has three form analogue to digital, digital to analogue, digital to digital form.
  • Inverter is used to convert DC electricity from solar panels, batteries or fuel cells to AC; micro the inverter for converting DC power from solar panels to AC for the electric grid; UPS uses inverter to supply AC power when main power is unavailable, induction heating while converter convert AC to DC detect amplitude modulated radio signals, supply polarized voltage for welding.
  • One of the disadvantages of the inverter is that it is not ideal for inductive AC and motor load, sensitive electronic devices can be damaged by poor waveforms by low batteries but in convert has poor current overload capacity, better quality automatic regulators are more expensive than mechanical regulators. 
A key difference between Converter and Inverter:
  • Inverters are typically a lot more complex compared to the converters.
  • A converter is used in pretty much all application while the inverter is used in uninterruptible power supplies.
  • Inverter changes voltage as well as type, A converter changes the voltage but doesn't its type while an inverter changes voltage as well as type.

Difference between TDMA FDMA CDMA

This page describes FDMA versus TDMA versus CDMA provides a difference between FDMA, TDMA and CDMA technologies. This post also describes multiple access techniques to make use of common resources by multiple users or subscribers.

FDMA:
  • FDMA stands for frequency division multiple access, Here all entire band of frequencies is divided into multiple RF channel. Each carrier is allocated to different users.
  • Segment the frequency band into disjoint subbands.
  • Every terminal has its own frequency uninterrupted.
  • Filtering in the frequency domain.
  • FDMA is simple. established, robust.
  • FDMA is inflexible, frequencies are a scarce resource
  • Cell capacity is limited.
  • FDMA is a hard handoff.
  • Power efficiency reduced.
TDMA:
  • TDMA stands for time division multiple access, here entire bandwidth is shared among different subscribers at fixed predetermined or dynamically assigned time slots.
  • Segments sending time into disjoint time slots demand driven or it would be fixed patterns.
  • All terminal are active for short periods of time of the same frequency.
  • Synchronization in the time domain.
  • TDMA is established fully digital, flexible.
  • TDMA is guard space needed, synchronization difficult.
  • Cell capacity is limited.
  • TDMA is a hard handoff.
  • When we are using TDMA full power efficiency is possible.
CDMA:
  • TDMA stands for time division multiple access, here entire bandwidth is shared among different subscribers at fixed predetermined or dynamically assigned time slots.
  • Spread the using orthogonal codes.
  • All terminals can be active at the same place and also at the same moment uninterrupted.
  • Signal speration for code puls special receivers.
  • CDMA is flexible, less frequency needed soft handover.
  • CDMA is a complex receiver, need more complicated power control for senders.
  • No absolute limit on channel capacity but, it is interference limited for a system.
  • CDMA IS soft handoff.
  • When we are using CDMA full power efficiency is possible.









Difference between half wave rectifier and full wave rectifier

The half wave and full wave rectifier have a significant difference. A rectifier converts AC voltage into pulsating DC  output voltage. A half wave rectifier is an electronic circuit which converts only one half of the AC cycle into pulsating DC output. On the other hand, full wave rectifier is an electronic circuit which converts the entire cycle of AC into pulsating DC output. This page gives the half wave vs full wave rectifier provides the difference between half wave rectifier and full wave rectifier

Half wave rectifier:
  • A rectifier which rectifies only one half of each AC supply. 
  • The frequency of the output signal is exactly the same as that of the input signal.
  • Half wave rectifier gives discontinuous and pulsating DC output, Half wave rectification involves a lot of wastage energy.
  • Half wave rectifier is unidirectional.
  • Half wave rectifier efficiency around 40.6 %.
  • Half wave rectifier is only one diode is required.
Full wave rectifier :
  • A rectifier which rectifies both halves of each AC input cycle is called as full wave rectifier
  • It gives continuous and pulsating output.
  • The frequency of the output signal is double that of the input signal.
  • A full wave rectifier is bi-directional.
  • Half wave rectifier efficiency around 81.2%.
  • Full wave rectifier varies from 2 to 4, in case of a bridge rectifier.
A main key difference between half wave rectifier and Full wave rectifier:
  • Half wave rectifier is a low-efficiency rectifier while the full wave rectifier is high efficiency.
  • The losses due to saturation of the DC core in half wave rectifier and full wave rectifier also create a significant difference. The half wave process DC saturation of core, but this problem can be overcome in the full wave circuit.
  • Full wave requires more electronic components as compared to half wave rectifier. Thus requires double the number of diodes.
  • The ripple factor in case of half wave rectifier is compared to the full wave rectifier, for half-wave rectifier it is about 1.21 but for the full wave rectifier, it is about 0.482.
  • The full wave circuitry does not possess DC saturation of the transformer core because of the current in the secondary winding of the transformer and in opposite directions.
  • A half wave rectifier hs good voltage regulation however full wave rectifier provides better voltage regulation as compared to half wave rectifier.
  • Half wave rectifier does not require centre tapping of the secondary winding of the transformer while full wave rectifier centre tapping of the secondary winding of the transformer.
  • The fundamental ripple frequency in case of half wave rectifier is f, supplied input frequency 50 Hz while in twice the supplied frequency 2f (100Hz) in case of full wave rectifier.
  • The peak inverse voltage in case of half wave rectifier is equivalent to the maximum value of applied input voltage while in peak inverse voltage of full wave rectifier is twice the maximum value of applied input voltage.

Difference between TDMA and CDMA

TDMA technology was recent in more popular in Europe, Asian countries, Japan, whereas CDMA is widely used in North and South America but nowadays both technologies are very popular throughout the world. TDMA emerged and was utilized first but in CDMA is more recent technology gradually replacing TDMA. The main difference between these two techniques is in the way which the user share the same physical channel. This post gives more information about TDMA VS CDMA to better understand this topic.

TDMA:
  • In TDMA all slots are assigned cyclically.
  • Data rate overhead is between 20 to 30 %.
  • Transmission or receiving is allowed for only one user is given slot.
  • The transmission is noncontinuous.
  • All slot are assigned on demand.
  • Due to reduced inter-user interference, power control is less stringent.
  • It is essential to use digital data and also for modulation.
  • Overhead trade-off is the size of data payload and latency.
  • Multiple users are shared with a single carrier frequency.
  • Due to reduced inter-user interference, power control is less transmission.
  • Handoff is made simpler by using non-continuous transmission.
CDMA:
  • Power limited device.
  • Conversion needs to be extracted from the background.
  • It is difficult to distinguishing individuals when GP is low.
  • Fading would be reduced with a wide frequency spectrum.
  • It needs to have separate multipath signals with different delays by chip unit
  • The system performance will be degraded for every user when the total number of users increases.
  • GP is high when people speak a different language, which is easier to distinguish individual speakers.
  • CDMA uses a process called spread spectrum method, which scattering of digital bits in a pseudo-random manner and collecting them for interpretation.
  • While people talking random noise band playing occurs.
  • CDMA allows numerous user to use the channel at the same time while TDMA does not.
A main key difference between TDMA and CDMA:
  • The abbreviation of TDMA is time division multiple access while in CDMA stand for code division multiple access.
  • CDMA is continoous transmission while TDMA is discontinous transmission.
  • TDMA is segmented sending time into disjoint time slot demand driven or it to be fixed patterns whereas when CDMA has spread the spectrum using orthogonal codes.
  • In TDMA system synchronization in the time domain while in FDMA  signal separation using code puls special receivers.
  • In TDMA all terminal are active for short periods of time on the same frequency while in CDMA can be active at the same place at the same moment uninterrupted.
  • CDMA allows numerous users to use the channel at the same time while TDMA does not allow.
  • CDMA still faces some problems, high complexity, lowered expectations, will be integrated with TDMA or FDMA while in TDMA fixed network together with FDMA or SDMA used in many mobile networks.

Difference between LCD and LED

The main difference between the LCD and LED is that display of LED consumes less power and is the best for the picture quality when compared with the LCD  display, This post gives the main key difference between LCD and LED  to a better understanding of this topic.

LCD :
  • LCD stands for liquid crystal display.
  • LCD consumes less power. 
  • LCD can be driven directly from IC chips. Driver circuits are not required.
  • LCD has a moderate brightness level.
  • Comparatively less temperature limit. The temperature range is limited to -20 to 60-degree Celsius.
  • Due to chemical degradation, the lifetime is 50000 hours.
  • The viewing angle for LCD is 100 degree.
  • Operating voltage range is 3 to 20 VDC.
  • LCD is less expensive than LED. If you want to compromise a bit with a quality you can go for an LCD.
LED:
  • LED stands for a light emitting diode.
  • LED consumes more power than LCD.
  • Due to the high power requirement, LED require an external interface circuit when driven from ICs.
  • The brightness level is very good for LEDs.
  • Lifetime is around 100000hours.
  • Commercially available LEDs have an operating temperature range of -40 to 85-degree celsius
  • LED has a wide viewing angle.
  • Operating voltage range 1.5 V to 5 VDC.
  • If you are going to purchase LED, its expensive than LCD but have the quality of picture and better features than LCD.

A key difference between LCD and LED:

Here we will discuss the main difference between LCD and LED, specifically in reference to TVs based on the technology, picture quality, contrast ratio, resolution, viewing angle etc.

  • LCD stands for liquid crystal display while LED stands for the light emitting diode.
  • The cost of the LED is more than LCD.
  • The resolution of LED is much better than that of LCD.
  • The LED is a PN junction diode which emits visible when the forward bias applies across it while in LCD uses liquid filaments which are filled between glass electrodes for the emission of light.
  • The direct current reduces the life span of LCD while in LED has no effect on it.
  • The switching time of the LED is less than LCD.
  • The LCD uses mercury which pollutes the environment whereas the LED does not use mercury.
  • LED is a faster response time compared to LCD.
  • The display area of the LED is less compared to the LCD.
  • The LED comes with a wider viewing angle than the LCD.
  • LED display gives good quality than LCD.
  • LED provides better color accuracy than LCD.
  • The LED consumes more power as compared to the LCD.
  • The LED uses gallium arsenides which when heated emits light whereas LCD uses a liquid crystal which is energized and provides light.
  • LCD is not good to create black area hence not good have contrast as LED while in LED has better contrast and black level as it produces better black areas which give a better quality of the image.
  • The LCD uses cold cathode fluorescent lamp which provides the backlight of the screen whereas the LED uses the P-N junction diodes for the displaying the light.