|
Sr# |
Bi-Polar
Junction Transistor (BJT) |
Metal Oxide Field
Effect Transistor (MOSFET) |
|
1 |
It is a Bipolar Device |
It is majority carrier
Device |
|
2 |
Current control Device |
Voltage control Device. |
|
3 |
Output is controlled by
controlling base current |
Output is controlled by
controlling gate voltage |
|
4 |
Negative temperature
coefficient |
Positive temperature
coefficient |
|
5 |
So, paralleling of BJT is
difficult. |
So, paralleling of this
device is easy. |
|
6 |
Dive circuit is complex.
It should provide |
Dive circuit is simple.
It should provide |
|
7 |
constant current (Base
current) |
constant voltage (gate
voltage) |
|
8 |
Losses are low. |
Losses are higher than
BJTs. |
|
9 |
So used in high power
applications. |
Used in low power
applications. |
|
10 |
BJTs have high voltage
and current ratings. |
They have less voltage
and current ratings. |
|
11 |
Switching frequency is
lower than MOSFET. |
Switching frequency is
high. |
Auto Transformer Tap Changing: Working Principle, Switching Sequence and Applications Auto transformer tap changing is a practical method of adjusting transformer output voltage without unnecessarily interrupting the electrical supply. In power transmission and distribution networks, the load does not remain constant throughout the day. As load current changes, voltage drops across transformers, cables, feeders, and transmission lines also change. A tap-changing arrangement compensates for these variations by modifying the effective number of turns in the transformer winding. A reactor-type on-load tap changer uses a center-tapped reactor, selector switches, and a bypass or short-circuiting switch to transfer the load from one tap to the next. The reactor limits the circulating current during the transition, allowing the tap position to change while the transformer continues supplying the connected load. This article explains the auto transformer tap-changing working principle , switch...
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