Bipolar transistor vs. MOSFETs

[emavil]

transistor vs mosfet

I saw RGB LED circuit of some MICROCONTROLLER guys that displays colors of the rainbow (PWM) that uses MOSFET instead of a driver transistor. I observed that as time goes, the regulator (7805) is still cool.

I also constructed my own version of RGB lighting, the only difference is that instead of using MOSFET I manage to pick 3pcs of BC557 bipolar transistors. I'm not familiar with the functionality of MOSFETs.

As a power my circuit, i observed that as time goes, the regulator (7805) gets quite hot.

Anyone who has an idea what is really the advantage of using MOSFETs in driving not only LEDs as well as motors.

 

[IanP]

mosfet vs transistor

In case of BJTs look at their Vcesat parameter ..
In case of MOSFETS look at their Rdson value ..

If power-converted-to-heat means V*I, or I²R, it is easy to guess which component will loose/convert more energy into heat ..

Regards,
IanP

 

[fazan83]

bipolar vs mosfet

Mosfet consume less power. BJT consumer large power. Mosfet also can help to simplify the design.

 

[dkace]

how to check mosfet transisitor

Check the physics of the devices as IanP says and you will understand the difference. In MOSFET you just control a gate with a signal that is not propagated to the rest of the device trather than acting as a field creator.
In BJT you have to supply the base with a current that will flow through the device in order to operate. More power is allready implemented by there operation. If you don't want to go into physics, just follow IanP suggestion. If you decide to work with MOSFET as a controler or a driver of a LED circuit, then just say so and help will be at your screen!

D.

 

[fazan83]

mosfet vs bipolar

Check the physics of the devices as IanP says and you will understand the difference. In MOSFET you just control a gate with a signal that is not propagated to the rest of the device trather than acting as a field creator.
In BJT you have to supply the base with a current that will flow through the device in order to operate. More power is allready implemented by there operation. If you don't want to go into physics, just follow IanP suggestion. If you decide to work with MOSFET as a controler or a driver of a LED circuit, then just say so and help will be at your screen!

D.

D,
DO you know how to decode text signal from hyperterminal and then display it using RGB LED Driver? The RGB LED Driver of course use mosfet as it row controller. And for collum it use constant current IC conttroller.

The anode of the LED will be connected to mosfet source.
Meanwhile the Cathode of the each color of RGB LED will connected to the constan current IC.

Can you please advise how the system work? how to decode the data from hypertermina to drive the collum and row circuit?

 

[sonal]

mosfets vs transistors

The metal-oxide-semiconductor field-effect transistor (MOSFET, MOS-FET, or MOS FET), is by far the most common field-effect transistor in both digital and analog circuits. The MOSFET is composed of a channel of n-type or p-type semiconductor material (see article on semiconductor devices), and is accordingly called an NMOSFET or a PMOSFET (also commonly nMOSFET, pMOSFET, NMOS FET, PMOS FET, nMOS FET, pMOS FET).

 

[dkace]

difference of transistor and mosfet

D,
DO you know how to decode text signal from hyperterminal and then display it using RGB LED Driver? The RGB LED Driver of course use mosfet as it row controller. And for collum it use constant current IC conttroller.

The anode of the LED will be connected to mosfet source.
Meanwhile the Cathode of the each color of RGB LED will connected to the constan current IC.

Can you please advise how the system work? how to decode the data from hypertermina to drive the collum and row circuit?

Well I don't know that one, but we can try to find a way doing it. It seems like fun.

Tell me what will be the signal exactly. When you say text --->LED row you want to display the text that is on your screen on a hyperterminal to a LED panel?

Where this text come from? Can you output it from a serial port of the PC? What is the origin of the text? Is it your keyboard?Is it a program?

Let's do it as an exercise and see where it will get us!!!

D.