UPPCL JE 2016 Electrical question paper with Solution (Evening Shift)

The LED has two pins called anode and cathode.The anode is the longest pin and is connected to the most positive voltage. The cathode is connected to the most negative voltage. They must be connected correctly for the LED to work.

A Maxwell bridge is a modification to a Wheatstone bridge used to measure an unknown inductance (usually of low Q value) in terms of calibrated resistance and inductance or resistance and capacitance. When the calibrated components are a parallel resistor and capacitor, the bridge is known as a Maxwell-Wien bridge.

The mixture of dung and water which enters the biogas plant in semi-liquid form is called “undigested slurry.

Regardless of specific feed used, biogas generation proceeds most efficiently when raw materials fed to the digester have the desired pH and carbon-to-nitrogen ratio (C: N).

Bacteria thrive in a slurry with a pH value of around 7 and consequently if the input slurry has a pH close to 7. fermentation proceeds more smoothly.

A high C: N ratio means that the nitrogen will be exhausted before carbon is digested. Conversely. a low C: N ratio i.e., too much nitrogen in relation to carbon results in high ammonium concentrations which tend to become toxic to anaerobic bacteria. Generally for quality biogas production pH ranging between 6.5 – 8.5 is optimum.

The P-side emitter in UJT is Heavily doped.

A Unijunction transistor is a 2-layer, 3-terminal solid-state switching device (silicon). It is also called as the double-base diode. The device has a unique characteristic that when it is triggered, its emitter current increases regeneratively (due to the negative resistance characteristic) until it is restricted by the emitter power supply. Since the device has one PN junction and three leads it is commonly called UJT.

A unijunction transistor (UJT) is a three-terminal semiconductor device having one p-n junction. It is mostly used as a switch and commonly employed in timing circuits, SCR/Triac triggering circuits, oscillators, and so on.

It consists of an n-type silicon semiconductor bar having ohmic contacts at each end. The two end connections are called base-1 and base-2, which are labeled as B1 and B2, respectively.

This n-type semiconductor is lightly doped. Near to the terminal B2, a small heavily doped p-region is alloyed which forms a p-n junction with the bar.

The terminal to this junction is called emitter (E). The resistance of the silicon bar is called InterBase resistance RBB, i.e. the resistance between the terminals B1 and B2.

The common base-emitter has low input impedance (on the order of 50 to 500 Ohms) and high output impedance (on the order of 1 to 10 MegaOhms). The Current gain(alpha) is less than unity.

The Unijunction transistor is a 2-layer, 3-terminal solid-state switching device (silicon). It is also called the double-base diode. The device has a unique characteristic that when it is triggered, its emitter current increases regeneratively (due to the negative resistance characteristic) until it is restricted by the emitter power supply. Since the device has one PN junction and three leads it is commonly called UJT.

 

A unijunction transistor (UJT) is a three-terminal semiconductor device having one p-n junction. It is mostly used as a switch and commonly employed in timing circuits, SCR/Triac triggering circuits, oscillators and so on.

It consists of an n-type silicon semiconductor bar having ohmic contacts at each end. The two end connections are called base-1 and base-2, which are labeled as B1 and B2, respectively.

This n-type semiconductor is lightly doped. Near to the terminal B2, a small heavily doped p-region is alloyed which forms a p-n junction with the bar. The terminal to this junction is called emitter (E).

The total resistance of the silicon bar from terminal B₂ to B₁ with the emitter open is called the InterBase resistance RBB. Thus,

RBB = RB₁ + RB₂, with emitter open

where RBB is typically in the range of 4 kΩ to 10 kΩ and RB₁ is usually greater than RB₂. Hence the resistance of the base terminal is very high in UJT.

Based on the head of the water level, the hydraulic turbine is classified as low head, medium head, and high head turbine.

Low head turbines: These turbines work under low heads ranging between 3 and 50 m of water. They are designed for higher discharge rates E.g. Kaplan Turbine.

Medium head turbines: These turbines work under medium heads ranging between 55 and 400 m. They are designed for medium discharge rates E.g. Francis Turbine.

High head turbines: These turbines are designed only for low discharges and work under high heads ranging above 300-400 m.E.g Pelton Turbine.

When the connected load in a network is not linear, i.e. does not draw sinusoidal currents, the load currents will distort the sinusoidal voltages. This deviation from a sinusoidal voltage or current waveform is called Draconic distortion.

Harmonic is multiple of the fundamental frequency and it can be voltage and current in an electric power system are a result of non-linear electric loads. Harmonic frequencies in the power grid are a frequent cause of power quality problems.

There is no such thing as “DC Harmonics”, as DC is defined as zero frequency.

In nuclear energy Nuclear fuel such as U₂₃₅ is used in the Nuclear reactor to release the heat energy. Till now we don’t have enough resources to convert that much heat energy by using solar energy.