bjt and its lack lustre nature

[jeffrey samuel]

in general we cant imagine an amplifier with out bjt

but years passed by has shown the vast disadvantage of using it in real time applications

can anyone post the various reasons for that

 

[rahdirs]

MOSFETs don't need current on their control pin, but require more voltage. Some don't turn on fully at 5v, some do. A BJT is limited to something like 0.3v for the lowest voltage drop on the current path, but MOSFETs are only limited by their resistance (rDSon). MOSFETs are usually more efficient switches for power supplies, etc where you want a switch rather than an amplifier.

Power MOSFETs have faster switching times, no second breakdown , and stable gain and response time over wide temperature ranges.

To operate bipolars at high switching frequencies and high current, you have to prevent the devices from going into hard saturation as this will increase storage times (making it difficult to switch off quickly) but then cause the device to dissipate more heat due to higher Vce-sat.

One place that MOSFETS were proved to be a poor choice is in low distortion audio power amplifiers.

So maybe we can use IGBTs combining the advantages of both