KNOW HOW FUEL GAUGE WORKS IN VEHICLES !

We generally see fuel gauge in cars and motorbikes. They tell us the level of fuel in the fuel tank very accurately. Have you ever imagined how this gauge works and gives us reading that is always correct? We will understand the working of fuel gauge in this article.

The fuel gauge is a simple device. As a rule of thumb, it doesn’t even indicate/calculate the quantity of fuel in liters (or gallons), since all that is needed to alert the driver is the amount of fuel relative to the tank’s capacity. In this regard, fuel gauges have just two main markings – F for Full and E for Empty. Some have a “½” marking, too, to show half-tank.

The basic electromechanical fuel gauge consists of very few parts. The first part of this system is the sending unit. The sending unit is located in the fuel tank of the car. It consists of a float, usually made of foam, connected to a thin, metal rod. The end of the rod is mounted to a variable resistor. A resistor is an electrical device that resists the flow of electricity. The more resistance there is, the less current will flow. In a fuel tank, the variable resistor consists of a strip of resistive material connected on one side to the ground. A wiper connected to the gauge slides along this strip of material, conducting the current from the gauge to the resistor. 

If the wiper is close to the grounded side of the strip ( represented by the circuit in the figure), there is less resistive material in the path of the current, so the resistance is small (and current is high). If the wiper is at the other end of the strip, there is more resistive material in the current's path, so the resistance is large(and current is low).

The second part of this system is the fuel gauge which is a current meter. At low fuel levels the resistance will be high and at high levels the resistance will be low. The current from the resistor goes to a gauge that reacts to the amount of current flow. At high resistance the current will be low and the needle on the gas gauge will be low. At low resistance (full tank) the current will be high and the needle on the fuel gauge will reflect that. This is how the fuel gauge works.

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KNOW WHY KEY IS USED IN TORQUE TRANSMISSION !!

We come across various mechanical components on day to day basis, But we ignore the functionality of various components. We are going to discuss the functionality of one such component. You might have seen shaft and other mechanical components connected with a key. Have you ever imagined why this key is used? Let us explore the reason for the key in this article.

A key is a machine element that is used to connect a shaft to other machine elements like Gears, Pullies, Couplings, Sprockets or Flywheels. The key prevents relative rotation between the two parts and may enable torque transmission.

The key will have a provision in both the shaft and the machine element which needed to be connected. this is called Keyway. These keys are temporary fastening elements and are subject to the crushing and the shearing stress.

Various types of the key are used in power transmission are square key, flat key, Dowel Key and so on.

WHY KEY IS USED IN POWER TRANSMISSION :

Let us assume a situation where the key is not used in power transmission as shown in the figure below. When there is a sudden rise in torque, there might be chances of slip between components.

The key ensures the connection transmits the load, power & rotation without slipping and within the accuracy requirement of the design. Without the key the components may slip and this might result in loss of efficiency.

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KNOW WHERE DOES ELECTRICITY GO AFTER GROUND !

We all know that every electrical equipment is grounded as a safety measure. The ground wire in an electric outlet is a safety valve; any undesired electricity (positively charged energy) flows to the ground and prevents us from shock. But have you ever imagined where this electricity goes from the ground? We will discuss about this in this article.

For clearly understanding this concept consider our household wiring system. To prevent static electrocution the grounding or earthing is done. Also the neutral passes through all household systems and is commonly collected near the transformer and grounded. Thus it returns through the source which produces it. See the below diagram for further explanation.

"Ground" is not where the electricity goes, it's just a term for zero potential. Household power is AC, so charge never really goes anywhere. The same amount of charge is drawn out from the Earth as is put back in. Electricity doesn't work by pumping an extra charge into something. We also know the law of conservation of energy that energy can neither be created nor destroyed. When you connect a circuit to the ground - it completes the circuit back to the source.
So, in short in order to complete the circuit it returns back to the source.
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