Sunday, 4 January 2015

BJT or MOSFET—What to Pick for Your Project

Beginners, newly toying with Electronics Science applications are often unable to decide what to choose appropriately for their project-- a MOSFET or BJT. We have to keep in mind there is a distinct fine line—MOSFET is controlled by voltage, while BJT is controlled by current. Of course they have their salient features that you can learn easily with aid of analog electronics tutorials. You need to consider a set of factors to choose transistor for your project—drive voltage, required power level, load voltage, speed and efficiency are among many.

  • Earlier, BJT was a major hit. It was the easiest to enhance, the ease of fabricating transistor rendered BJT cheap and effortless to use. BJT’s linear, simple current gain is one feature that made it very popular for several applications. BJTs also possess less capacitance by control pin. 

  • In a battery-charged electronics device, where the source of power is limited and the load is not constant, using BJT is NOT a good idea. But if the current flow is predictable as in LED, BJT can come in handy. Here you can easily improve the efficiency by setting base-emitter current into a split fraction LED current. 

  • MOSFET is very useful as input impedance and current gain both are high. This is one of the most advantageous aspects of MOSFET. If you’re opting for switching circuit applications, MOSFET speed is super-high due to reduced amount of carrier operations. MOSFET is more energy efficient in this context. But BJT loses power as long as it’s switched on. Analog electronics tutorial can demonstrate the operating modes of transistors with fine illustrations. 

  • Low resistance consistency sustaining the operating region, is one of the chief reasons to pick MOSFET for. It can also endure good level of heat—not losing stability owing to thermal change.

Instead of humming over one fixed transistor in particular, it’s better to build a more innovative circuit by mix and match, by taking advantage of both—high input impedance and little power consumption of MOSFET and high-current-travel ability of bipolar transistors. In order to better the performance of the circuit, you have to imagine a better combination.

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