It does not store any personal data.As usual, rules of thumb and knee-jerk answers can be misleading, especially when forgetting the constraints in the original guidelines that were then dumbed down to make 'rules' for the non-thinking.įETs are voltage-controlled, and BJTs are current-controlled.

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Also it doesn’t has to be either BJT or MOSFET, they can as well be combined together to create innovative circuits that take advantage of the high-input-impedance and low-power operation of MOSFETs and the very-high-frequency operation and high-current-driving capability of bipolar transistors. ConclusionĬarefully selected transistor can enhance the performance of your project. Bcause you can simply set the base-emitter current to be a small fraction of the LED current to achive better efficiency. If a BJT is used to power something with a predictable current draw like LEDs, using BJT isn’t as bad. In a battery-powered device where you have limited power and the load is variable and often low, using BJT is a bad idea. The external resistance generates additional efficiency losses. For instance the MOSFETs can be easily placed in parallel, but the BJT cannot unless external emitter resistors are added. Transistors are often connected together to form useful circuits. Also the BJT generally has a 0.3v voltage drop in the input pin, and it takes a lot of base current to do that. MOSFET is usually more efficient switches for power supplies. BJT will consume more power because it’s wasting current when it’s switch on. Rdson increases with temperature and may double over ambient temperature values. Rdson is dependant on drive voltage, load current. A MOSFET has an on resistance Rdson rather than Vsat. less than 10V and around 1A, small BJT could be a good choice. Bipolar have on state voltage drops (Vsat) dependant on load current, drive current & specific device type. However MOSFET is more tolerant to heat (stable to thermal changes) and can simulate a good resistor.Īt low power and voltages application – e.g. Arduino).īJT can switch faster than MOSFET due to the less capacitance at the control pin. Therefore BJTs are more suitable than MOSFETs for driving low-power LEDs and similar devices from Micro Controllers Unit (e.g. On the other hand, BJTs that can be driven by Arduino (~5V DC) are easier to find, and generally cheaper. They are not as common as standard MOSFET that requires at least 10V or more Vgs (gate-source voltage) to fully turn on. When used with Arduino which can only produce an DC output voltage of 5V, we are limited to using logic level MOSFET. Buy MOSFET’s for Arduino Projects on Banggood or Amazon.driving a few LEDs or 5V DC motor etc, since most of the readers on this blog are of Arduino and Raspberry Pi hobbyists. I will mainly focus on low power consumption applications e.g. When choosing which one to use in your application, one needs to consider many factors including power level, drive voltage, load voltage,switching speed, efficiency, cost, etc. There isn’t a straight-forward and definite answer to the question which one is better. Please read our Affiliate Link Policy for more information.Īs explained in my previous articles, BJT is current-controlled device where MOSFET is voltage-controlled, both with unique characteristics and their pros and cons. This helps support the free content for the community on this website. I receive a commission (at no extra cost to you) if you make a purchase after clicking on one of these affiliate links. Some of the links on this page are affiliate links.

Bjt vs mosfet