Tagged Questions
4
votes
3answers
118 views
How does a dual gate MOSFET reduce Miller effect?
How does a dual gate MOSFET reduce Miller effect? I am trying to gain a global understaning of the physics behind them, not necessarily exact formula's that come with it other than maybe some for ...
2
votes
1answer
97 views
Simplest design approach for PWM control with power MOSFET
I'm designing an application in which the current running into a load is controlled by PWM. A microcontroller generates a PWM cycle at 20kHz and this signal is used to control a MOSFET which is ...
1
vote
2answers
106 views
MOSFET for PWM application
I'm designing an application where a power logic level MOSFET is driven using a 5V PWM signal at 20kHz.
The drain current will be approx. 10A and the voltage of the load 12V.
I looked into the ...
-6
votes
2answers
69 views
Any body could tell me which MOSFET is perfect for Input Dc 200-2800 and Output 15V @ Output Current 3A [closed]
Please Help me to find MOSFET or IGBT for High Voltage Dc Input from dc input 200-2800V and output 15V @ output Current 3A
This is for dc-dc converter which we will use MOSFET.
1
vote
2answers
93 views
Question about using N-channel MOSFETs in a current sharing controller
My question is specifically regarding LTC4353 :
Product link: http://www.linear.com/product/LTC4353
Datasheet link: http://www.linear.com/docs/41582
Looking at the diagram on the product ...
1
vote
3answers
305 views
Any way to use N-channel mosfet in P-channel configuration?
In my application, I need the HIGH signal to turn a device OFF and vice versa. Clearly, this is P-mosfet configuration. However, I only N-mosfet on hand.
Is there any clever way to utilize N-mosfet to ...
-1
votes
2answers
340 views
Bootstrap circuit function
I had some question about the bootstrap capacitor on gate driver.
First, the bootstrap capacitor is used because the voltage on the high side drivers gate need to be about 10-15 volts higher than the ...
5
votes
2answers
435 views
Switching a current with an NPN transistor and a P-MOSFET
Just learning about transistors and I'm trying to clearly understand how to apply them for basic switching, in terms of the two standard cases, i.e., Active HIGH behavior and Active LOW behavior. For ...
1
vote
2answers
655 views
Transistor / mosfet for PWM dimming of 30W RGB LED
I am building a led mood light with a high power RGB LED (30W) using 3 constant power supplies for each color.
These are the items I had in mind (but open to suggestions):
30W Integrated RGB LED ...
1
vote
1answer
84 views
Does this product page contradict the corresponding datasheet?
I'm currently using N-channel MOSFET's my hobby circuit, and have had two go out on me. As a result, I'm studying them a little more and making sure I'm not doing anything that might harm them.
On ...
2
votes
1answer
220 views
What makes an “rf transistor” different from an ordinary transistor?
I have been looking at various types of transistors that can switch at higher speeds than my clunky but powerful IGBT, and I came across these things called "rf transistors" or "rf mosfets" which can ...
-2
votes
1answer
112 views
Fet array operation [closed]
Can anyone explain to me the operation of the following FET arrray .
http://www.diodes.com/datasheets/DMN2019UTS.pdf
2
votes
2answers
783 views
Why is the Triode operating region of a MOSFET named such?
If triodes were used for amplifiers, why is the triode region generally used for digital and the saturation region generally used for analog? Am I missing a fundamental understanding of the MOSFET's ...
1
vote
2answers
292 views
MOSFET or bipolar to drive a solenoid valve?
I have to drive a 12V solenoid valve. In the datasheet it's written: Power: 8 W. So the current drawn by the solenoid is 0.666 A.
Usually, to drive small relay (about 10 or 20 mA) I use a bipolar ...
1
vote
3answers
185 views
Transistor setup for large motor circuit
I am building a relatively simple circuit which essentially consists of two lead acid batteries rated at 12V and two motors rated at 12V. My original plan is to wire them all in series, and control ...
4
votes
2answers
2k views
P-Channel MOSFET high side switch
I am trying to reduce the power dissipation of a P-Channel MOSFET high side switch. So my question is:
is there any way in which this circuit can be modified so that the P-Channel
MOSFET will ...
1
vote
3answers
256 views
MOSFET IRF7832 to turn on LED strip
I am trying to use a IRF7832 MOSFET {datasheet here} to control a short LED strip.
I have connected the LED strip between 12 V and drain and 0V to gate and source. The LED strip has 6 strings of 3 ...
1
vote
1answer
238 views
Pulling a pin to 12 V using 3.3V
I'm building a boost converter and want to implement a shutdown feature. The particular chip I'm using, LM3478, has a shutdown feature which is activated by a high level on the frequency adjust pin. ...
3
votes
3answers
677 views
P-Channel MOSFET Drain-Source Polarity in Power Switch Application
I'm looking at using the LTC4412 power switch in an application. From the datasheet, here is the typical application circuit: :
In the application circuit, an FDN306P p-channel MOSFET is used.
I'm ...
12
votes
2answers
1k views
Selecting a MOSFET for driving load from logic
I'm looking to drive a magnetic door lock from an Arduino. I've found a question about driving a solenoid from an Arduino, which includes a circuit that looks perfect for this kind of situtation:
...
3
votes
4answers
418 views
2
votes
1answer
467 views
MOSFET voltage controlled delay
As part of a project, I need to evaluate a clock distribution system involving transmission lines. As part of the system, we need to design a voltage controlled delay element consisting of a CMOS ...
3
votes
2answers
257 views
Common gate amplifier with load connected to negative DC bias
What's the difference between the following two circuits? Note that the capacitors are DC blocking, and the FET is on.
I understand that usually, the load is connected to ground. But what would ...
2
votes
3answers
364 views
Question about MOSFET behavior
I tried to simulate a circuit with mosfets in LTspice, but it's still hard to understand how they work
What I observed:
For N-channel MOSFETs (as in the picture above)
a) Current flow through ...
1
vote
2answers
2k views
W/L Ratio of a MOSFET
In the schematic builder that calculates voltages/currents/transient analysis that we have been provided for the electrical engineering course, MOSFETs have the parameter "W/L Ratio".
I figured that ...
3
votes
2answers
2k views
What is the formal definition of Quiescent Point?
What is Quiescent Point? Is it necessary for it to be related with any V vs I , I vs I, or any such characteristic curves intersection point?
0
votes
3answers
664 views
Why won't my MOSFET work?
I am having trouble getting my N-channel MOSFET to work. I am using the MOSFET to control a DC motor. I have the the positive end of 5V power supply going to my motor and from the motor to the drain. ...
0
votes
1answer
354 views
difference between output resistance, ro, and finite output resistance Ro?
What is the difference between the concept/meaning of output resistance, ro, and finite output resistance Ro in context of a circuit with MOSFETS (ie. a MOS current mirror)?
thanks
1
vote
1answer
222 views
Features values of typical BJT/MOS transistors
Is there a page that lists the values of all the features of typical BJT/CMOS transistors? e.g. ON-resistance, gate/base capacitance, amount of power the D-S/C-E junction is able to hold etc.
Of ...
5
votes
2answers
357 views
Transistor in saturation mode?
I was wondering why do we so often want out transistor to work in saturation mode? Ie. For a MOS Current Steering Circuit we want our transistors to operate in the saturation region....
1
vote
1answer
408 views
MOSFET Turns on without voltage on the gate?
I am using the following transistor to turn a motor on and off:
http://pdf1.alldatasheet.com/datasheet-pdf/view/418991/INFINEON/IPP096N03LG.html
I am applying 12V to the drain and 0V to the gate... ...
3
votes
4answers
1k views
Question about the basic differences between a MOSFET and a FET
I'm still new to all this stuff, but I'm slowly trying to understand. I'm getting most of my information from "Getting Started in Electronics" (Forrest Mimm's book)
Okay, so MOSFETs allow current to ...
20
votes
2answers
730 views
When to use what transistor
So there are several types of transistors:
BJT
JFET
MOSFET
Combine all that with the various flavors of each (NPN, PNP, enhancement mode, depletion mode, HEXFET, etc) and you've got a wide array ...
14
votes
3answers
12k views
Switching DC with MOSFET: p-Channel or n-Channel; Low Side Load or High Side Load?
I think, it is time I understand working principle of MOSFET transistors...
Suppose that;
I want to switch voltage on a resistive load by a MOSFET transistor.
Any control signal between -500V ...
9
votes
3answers
2k views
Equivalent circuit of a solid state relay
I want to switch 50V AC voltage. Maximum drained current will be 5A. Frequency is 50Hz. Switching speed is not important, can be real slow, it is not a problem in my application.
I wanted to use ...
13
votes
4answers
2k views
Why is a MOSFET triggered by Vgs and not Vgd?
Looking carefully at this diagram of one type of MOSFET:
(found in this application note)
We can see the device is virtually symmetrical. What makes the gate reference itself to the source and not ...
10
votes
4answers
1k views
Unnecessary Transistor and FET resistors?
I commonly see weak pull down resistors at the base of NPN transistors. Many electronic sites even recommend doing such things, usually specifying the value as something like 10x the base current ...
2
votes
3answers
269 views
Do I need to duplicate the 4th “substrate” connection when building CMOS gates out of discrete transistors?
All CMOS digital integrated circuits I've ever seen connect all the nFET substrates together to GND.
In particular, the IC CMOS NAND gate has one nFET that has its substrate connected to GND, but its ...
10
votes
2answers
917 views
How to choose a switch?
There seem to be about 4 major flavors of transistors, and then there are NPN/PNP versions. There are also relays, SCRs, and TRIACs.
When I need an microcontroller-controlled switch, what rules of ...
13
votes
4answers
4k views
When is a MOSFET more appropriate as a switch than a BJT?
In my experimentation, I've used only BJTs as switches (for turning on and off things like LEDs and such) for my MCU outputs. I've been repeatedly told, however, that N-channel enhancement-mode ...
