Home Appliance

Tube light 

Circuit diagram of tube light.

Celling fan  

Refrigerator  

The basic principle of refrigeration is simple . You simply pass a colder liquid continuously around the object that is to be cooled. This will take heat from the object.

It has 4 main components

• Compressor 

• Condensor

• Evaporator

• Throttling device

CT (Current Transformer)

What is CT(Current Transformer) ?

Instrument Transformer are two types CT(current transformer) and VT(voltage transformer).

For stepping down voltages and current for metering and measurement. CT is a type of instrument that design to produce an alternating current in its secondary winding which is proportional to the current being measured in its primary.

figure of current and voltage transformer.

Above figure shows how CT is  working .

CT is just as working as other transformer , 

from above formula we can find out current in secondary side.

Is = secondary current

Ip= primary current 

Np= no. of turn in primary

Ns= no. of turn in secondary

some images of  CT use in field work.

What ampere current can human body tolerance ?

DC current effect on  of Human Body 

AC Current Effect on Human Body

Current	Reaction
1 milliamp	Just a faint tingle.
5 milliamps	Slight shock felt. Disturbing, but not painful. Most people can “let go.” However, strong involuntary movements can cause injuries.
6-25 milliamps (women)† 9-30 milliamps (men)	Painful shock. Muscular control is lost. This is the range where “freezing currents” start. It may not be possible to “let go.”
50-150 milliamps	Extremely painful shock, respiratory arrest (breathing stops), severe muscle contractions. Flexor muscles may cause holding on; extensor muscles may cause intense pushing away. Death is possible.
1,000-4,300 milliamps (1-4.3 amps)	Ventricular fibrillation (heart pumping action not rhythmic) occurs. Muscles contract; nerve damage occurs. Death is likely.
10,000 milliamps (10 amps)	Cardiac arrest and severe burns occur. Death is probable.

Different Material conductivity and resistivity

Table of Resistivity and Conductivity of Different Materials at 20°C

Material	Resistivity at 20°C	Conductivity 20°C
Air	1.3 × 1016 to 3.3 × 1016	3 × 10-15 to 8 × 10-15
Aluminum	2.82 × 10-8	3.5 × 107
Annealed copper	1.72 × 10-8	5.80 × 107
Calcium	3.36 × 10-8	2.98 × 107
Carbon (amorphous)	5 × 10-4 to 8 × 10-4	1.25 to 2 × 103
Carbon (diamond)	1 × 1012	~10-13
Carbon (graphite)	2.5 × 10-6 to 5.0 × 10-6 //basal plane	2 to 3 × 105 //basal plane
Carbon steel	-1010	1.43 × 10-7
Constantan	4.9 × 10-7	2.04 × 106
Copper	1.68 × 10-8	5.96 × 107
Deionized water	1.8 × 105	5.5 × 10-6
Drinking water	2 × 101 to 2 × 103	5 × 10-4 to 5 × 10-2
Fused quartz	7.5 × 1017	1.3 × 10-18
GaAs	5 × 10-7 to 10 × 10-3	5 × 10-8 to 103
Germanium	4.6 × 10-1	2.17
Glass	10 × 1010 to 10 × 1014	10-11 to 10-15
Gold	2.44 × 10-8	4.10 × 107
Grain oriented electrical steel	4.60 × 10-7	2.17 × 106
Hard rubber	1 × 1013	10-14
Iron	1.0 × 10-7	1.00 × 107
Lead	2.2 × 10-7	4.55 × 106
Lithium	9.28 × 10-8	1.08 × 107
Manganin	4.82 × 10-7	2.07 × 106
Mercury	9.8 × 10-7	1.02 × 106
Nichrome	1.10 × 10-6	9.09 × 105
Nickel	6.99 × 10-8	1.43 × 107
Paraffin wax	1 × 1017	10-18
PET	10 × 1020	10-21
Platinum	1.06 × 10-7	9.43 × 106
Sea water	2 × 10-1	4.8
Silicon	6.40 × 102	1.56 × 10-3
Silver	1.59 × 10-8	6.30 × 107
Stainless steel	6.9 × 10-7	1.45 × 106
Sulfur	1 × 1015	10-16
Teflon	10 × 1022 to 10 × 1024	10-25 to 10-23
Tin	1.09 × 10-7	9.17 × 106
Titanium	4.20 × 10-7	2.38 × 106
Tungsten	5.60 × 10-8	1.79 × 107
Wood (damp)	1 × 103 to 4	10-4 to 10-3
Wood (oven dry)	1 × 1014 to 16	10-16 to 10-14
Zinc	5.90 × 10-8	1.69 × 107

Full form use in electrical

Here is some of abbreviation use in electrical engineering 

1. PLC - Programmable Logic Controller 
2. DCS - Distributed Control System 
3. SCADA - Supervisory Control And  Data Acquisition 
4. HMI - Human Machine Interface
5. NO - Normally Open
6. NC - Normally Closed 
7. NL - Neutral Link 
8. KWh - Kilo Watt hour
9. Kvarh - Kilo volt ampere Reactive hour 
10. Kvah - Kilo volt ampere hour 
11. CT - Current Transformer
12. MCB - Miniature Circuit Breaker 
13. LA - Lightning Arraster

Why A.C measures in Ton not in kw or kva ?

Explanation

Why is air conditioner capacity measured in tons? You may have wondered this, especially since you know 4 ton  capacity air conditioner doesn't actually weight 4 tons. Here's what that 4 ton designation really means and why air conditioner capacity measured this way.

We know that the air conditioner's number of tons doesn't refer to its weight. In fact, this number refers to the amount of heat the air conditioner can remove from house within one hour. For example, a 4 ton air conditioner is able to remove 48,000 British thermal unit (BTU) from house per hour. One BTU is roughly equivalent to the heat that would be produced if you lit one match and burnt it all the way. One  ton of A/C capacity is equivalent to 12,000 BTU per hour.

Now we know what a ton means, but we still haven't answered the question of why the ton is the unit of measure for air conditioner capacity. Before the invention of the air conditioner . people who could afford it used large blocks of ice to cool their homes in the summer and refrigerate food. The ice was harvested during winter from frozen lakes and rivers.

But how did the use of ice to cool buildings lead to them "ton"?
It takes 143 BTU to; melt one pound block of ice at 32 degrees. Accordingly . if you have one - ton (2000 pound ) block of ice.It takes 286,000 BTU to melt completely . If that block of ice melt evenly over the course of the day, it absorbs heat at the rate of 11,917  BTU/hour. Rounded up we get 12,000 BTU/hour, or one ton of AC capacity.