78 Threads found on edaboard.com: Mosfet Npn Transistor
I'm rather new in power switching circuits.
I'm using a IRF 640 N-channel mosfet with the drain connected to approximately 9 V and the source to the load. I'm using the mosfet as a switch to turn on my power supply using a microcontroller this power supply will be fed into a 5V regulator and a 3.3 V regulator.
I have a few problem
Electronic Elementary Questions :: 27.12.2006 10:46 :: zhiling0229 :: Replies: 8 :: Views: 4694
I have discrete buck regulator (12V to 5V) in my design. PWM switching signal is generated from microcontroller. To drive high side mosfet (P/N) i would like to use TPS2818 gate drive IC.
My controller works on 5V. Can i feed this PWM to TPS2818? Can this generate proper drive for high side mosfet?
Analog Circuit Design :: 11.04.2007 00:43 :: niks :: Replies: 5 :: Views: 1752
Use one P-channel mosfet, with Vth about 6-8 volts.
connect its source to 10V, its gate to Vi input and its drain to Vo.
Electronic Elementary Questions :: 21.09.2008 02:18 :: Davood Amerion :: Replies: 10 :: Views: 774
I can not find the pn junction between the Drain and Source of the mosfet when the Gate and Drain are connected. Why people say it behaves like a diode? Is there anyone who can give me a cross section of the mosfet to illustrate it? Thanks a lot!
Electronic Elementary Questions :: 24.06.2009 11:31 :: lallaby :: Replies: 4 :: Views: 3179
It looks like the voltage that drives the mosfet's gate is to low ..
Digital mosfets (those designed to by driven by low-volt logic) like to be driven from roughly 4-5V, whereas standard mosfet shoud have the U close to 10Vdc ..
Try to add 1kΩ in parallel with , see attached drawing ..
Hobby Circuits and Small Projects Problems :: 11.03.2010 23:55 :: IanP :: Replies: 4 :: Views: 1731
If you asked this question some time ago the answer would be BJT, then mosfets became better and better, then IGBTs were available, and so on .. ..
Here is an article that could help you to choose:
Electronic Elementary Questions :: 10.06.2010 08:41 :: IanP :: Replies: 1 :: Views: 1678
High side mosfet Driver
I need to drive a mosfet to generate a constant current source,
the idea is to drive the mosfet in linear region to obtain a set current corresponding to the VOLTAGE Value .
Is this configurat
Analog Circuit Design :: 27.10.2010 07:37 :: themaccabee :: Replies: 5 :: Views: 3225
In this instance it?s better to use PNP (or P-channel mosfet), as all what you need to do is pull the base (or Gate) down to GND via a resistor ..
If you use npn transistor (I don?t know why you have mixed Source and Emitter ? these are pins of two different types of transistors) then you have to ensure that the Base is at (...)
Electronic Elementary Questions :: 05.12.2010 19:40 :: IanP :: Replies: 5 :: Views: 557
the mosfet gate turnon voltage is always in respect to its source terminal. So when the source voltage is at 4.5v and the gate is still at 3.6 it could already start turning on (logic level mosfet too ? ), so you drop the gate voltage to turn it on hard, sure it might not turn off then, no mystery there :smile:
You must level shift the gate
Electronic Elementary Questions :: 04.05.2011 08:13 :: xaccto :: Replies: 2 :: Views: 723
Post your circuit diagram..
How do you drive the High side mosfets?
You may need a high side driver
Robotics and Automatics Forum :: 30.06.2011 04:40 :: nandhu015 :: Replies: 19 :: Views: 2136
i am using PSMN2R0-60ES NXP N-mosfet as switch for 50V supply, i have got 10K resistor from 50V to Gate and npn transistor is making voltage divider with 10K resistor to control switching of Gate voltage. Drain of mosfet is at 50V.
now with out any load connected drop is 3.5 voltage accross drain and source.. (...)
Analog Circuit Design :: 16.12.2011 07:35 :: ahsoopk :: Replies: 3 :: Views: 2115
All the answer is referring to SWITCH operation ONLY, transistor and mosfet can operate other means too.
transistor Base current will go to Emitter (npn) when used as switch, in mosfet Gate current will not flow into Drain. In Opto-isolator, you will drive the LED part which will drive the (...)
Electronic Elementary Questions :: 15.04.2012 02:45 :: mpathma :: Replies: 8 :: Views: 2433
Just like raw examples of circuit
Hobby Circuits and Small Projects Problems :: 04.05.2012 17:34 :: tpetar :: Replies: 3 :: Views: 915
yes, it was me. I destroyed the Inverter by adapting the on-off switch to a remote on - off switch. I accidently sent 120vac into the on - off switch with a slip of the screwdriver.
I destroyed 1 power mosfet, 2 electrolytic caps exploded and vaporized some traces.
yes the transistor has a hole in it. Cant really tell if it is a 3B or a 3D
Electronic Elementary Questions :: 02.11.2012 20:33 :: sdowney717 :: Replies: 9 :: Views: 530
Hey peoples, i need your help here trying to power up a fan using a FET transistor.
Fan has 3 wire . Red Black Yellow
This is the mosfet im using.
and i also believe there is this component that my supervisor gave me but i can't find the details and the datasheet. i believe i
Analog Circuit Design :: 05.12.2012 21:54 :: InNeedOfHelp :: Replies: 30 :: Views: 782
Will my circuit work for the following goal?: When INPUT_N is HIGH (i.e. micro is not driving it and it is pulled up to 3.3V), VCC pin on device will have 24V. When Microcontroller drives INPUT_N to be LOW, VCC pin is at 0V (so device is off).
Should circuit below work as intended?
Analog Circuit Design :: 17.12.2012 13:44 :: mav1234 :: Replies: 5 :: Views: 316
mosfet is a transistor technology. It is an extention of the field-effect transistor (FET).
As with bipolar transistor, where you have npn and PNP, you can have two kind of FET (P-channel and N-channel).
When creating integrated circuits, using mainly P-channel mosfet (...)
Electronic Elementary Questions :: 23.06.2004 13:32 :: Big Boy :: Replies: 12 :: Views: 21350
Hi fellows !!!!
I need som help bout using mosfet in place of BJT in DC - AC Invertors / UPS Currently am using D313, 2N3055 & som other npn power transistors with 2.5Vbe I tried to use IRFP260 the same way but its not even conducting kindly help me out if it has any different way of operating or any important / basic point.
Waiting for a (...)
Analog Circuit Design :: 22.02.2005 05:07 :: Sikander Khwaja :: Replies: 4 :: Views: 877
we're currently designing a servo controller for these motors that we've started getting made up . The idea is to make a 'servo beater' for robotics applications, retailing at $15 - $20. Basic specs to include a variety of gearboxes (and nominal RPM outputs 40 ~ 250RPM), quadra
Microcontrollers :: 16.12.2005 07:52 :: fastcomponents :: Replies: 3 :: Views: 5962
I guess the ideal transistor is unidirectional (supposed to conduct in one direction)
But in reality, this is not always the case. Consider the use of transistors as switches in power conversion circuits.
If we use a power npn BJT as a controlled switch (current-controlled) it will conduct current from the collector to the emitter but (...)
Electronic Elementary Questions :: 03.01.2006 17:16 :: v_c :: Replies: 3 :: Views: 1765
but i need to know what happens if i use "n"region instead of "n+" in the mos transistor.
you will have a bad characterstic mosfet.
and i think it won't agree with current equations.
TeE ThE EdE
Electronic Elementary Questions :: 10.02.2006 09:08 :: tamerakshar :: Replies: 3 :: Views: 1455
What it does, it creates a higher voltage at the collector of the npn transistor than the Vdrive voltage. This ensures thet the Gate of the mosfet, drives it completely on so its on-resistance is the lower and hence the waste in heat produced in the mosfet is the minimum.
Usually the function of Bootstrap is to increase (...)
Electronic Elementary Questions :: 27.09.2006 07:03 :: platonas :: Replies: 4 :: Views: 1196
For simple understanding:
nmos is n-channel mosfet and is identical to npn transistor where you need positive voltage at the gate (base) to turn in on. pmos is identical to pnp and needs a negative voltage applied to the gate to turn it on. In CMOS, both transistors (nmos and pmos) are used.
When +ve voltage is applied, (...)
Analog IC Design and Layout :: 29.10.2006 19:45 :: invent :: Replies: 2 :: Views: 615
Use solid state relay based on photovoltaic element or integrated solid state relay. Look at IR site for details.
If you don't need galvanic isolation use approprated mosfet as switch.
PC Programming and Interfacing :: 08.11.2006 15:36 :: Hero :: Replies: 7 :: Views: 2057
Im getting a little bit confused as to which mosfet I need. I want it to act with the same 'turn' on characteristics as an npn Bi-polar transistor.
E.G High resistance when no voltage is applied to the gate and then a low resistance when a positive voltage is applied to the gate
I thought the correct (...)
Analog Circuit Design :: 24.11.2006 02:04 :: fala :: Replies: 2 :: Views: 463
i would used P-mosfet and N-mosfet rather transistor for driving motor IRFZ44 would and it's complementary will enough to drive your motor
Robotics and Automatics Forum :: 08.06.2007 06:43 :: e_eja :: Replies: 10 :: Views: 2544
the way you have biased the circuit is right only also the mosfet is stable even through temperature changes....
i think you have to be careful in the selection of resistors and caps to be used....
RF, Microwave, Antennas and Optics :: 25.07.2007 09:49 :: A.Anand Srinivasan :: Replies: 9 :: Views: 4466
how we can check a faulty npn & PNP
and faulty N-cahnnel and P-channel
Electronic Elementary Questions :: 26.08.2007 15:27 :: rabel126 :: Replies: 5 :: Views: 4744
I want to control a small vibration motor from a 5V TTL level. The motor should run on a separate 3.7V supply, which is able to handle the load. (The control signal is either 0 or 5V, never in between but maybe PWM modulated.)
What is the best/easiest way to accomplish this?
Will a standard npn transistor allow control of a lesser voltage (3
Electronic Elementary Questions :: 23.01.2008 08:56 :: tjak :: Replies: 3 :: Views: 1173
i want to know about the difference btween BJT , JFET and mosfet
Electronic Elementary Questions :: 04.02.2008 04:05 :: spiceymirza :: Replies: 2 :: Views: 52770
As you know the Base of the bipolar and the Gate of the mosfet transistors should have a definite voltage for them to work, say the Bias voltage. In fact when the switch in your circuit is off, as the npn transistor is also off, the Base of the PNP transistor has no definite voltage and that's called (...)
Analog Circuit Design :: 06.02.2008 13:53 :: naalald :: Replies: 10 :: Views: 827
Just as a idea because I don't know exactly what is your need (voltage in, voltage out, power level and so on), you can use a battery charger able to supply also load connected to the battery (e.g. Ansmann model ALCT 12-3) and a switching DC-DC post regulator (see attached circuit block schema). When the main power is down the battery will supply t
Professional Hardware and Electronics Design :: 26.06.2008 17:50 :: TekUT :: Replies: 18 :: Views: 6066
A logic level mosfet with sufficient low Ron will have lower voltage drop than darlington transistor.
Electronic Elementary Questions :: 28.07.2008 05:27 :: FvM :: Replies: 2 :: Views: 643
i want to create op-amp based firing circuit for mosfet. so plz do the needful for this..
awaiting for reply
Electronic Elementary Questions :: 26.06.2009 13:49 :: nilsone230384 :: Replies: 1 :: Views: 1263
GE1822 doesn't seem to be a valid transistor. Could it be a 2SK1822 - TO220 mosfet? It doesn't sound a likely drive for a TIP31/32 though. A picture may help as it may show a logo.
Service Manuals, Requests, Repair Tips :: 05.03.2010 13:20 :: keith1200rs :: Replies: 7 :: Views: 1222
You have to describe your situation and application in detail. Is it the DC pulse or impulse. Level of the DC? pulse width?
The basics would be to turn on a npn transistor and use this transistor to turn on POWER mosfetS, if you need more power add multiple mosfetets in parallel.
you can see a simple (...)
Hobby Circuits and Small Projects Problems :: 15.09.2010 09:50 :: lunar :: Replies: 5 :: Views: 1307
If you don't want to face issues while driving a switch from a 3.3V logic consider an inverter based on an npn (or N-channel mosfet) followed by P-channel mosfet (or PNP) working as a high-side switch ..
See fig.3 at:
Electronic Elementary Questions :: 28.11.2010 09:05 :: IanP :: Replies: 14 :: Views: 2125
There are many possibilities to be used in this situation.
Normally you keep the GND connection fixed and do control on the power supply line. Circuits are more tolerant to the voltage variation on the power supply compare to GND potential. See some possible configurations using BJT transistors, mosfet-P and a standard SPST 12V relay.
Electronic Elementary Questions :: 04.08.2011 06:08 :: mister_rf :: Replies: 2 :: Views: 953
Im trying to replace a transistor with a mosfet to drive the spark of a ignition coil.
I hooked up a npn (mpsA05) to pin 2 of a ignition coil to control/switch on and off the spark from a ignition coil. The performance/results appear to be good. See attached image of circuit and waveform. channel 2, the blue signal is my square wave (...)
Analog Circuit Design :: 31.08.2011 20:37 :: robismyname :: Replies: 10 :: Views: 3061
Sounds like you are using an unsuitable configuration of the switching transistor. We would usually utilize a PNP transistor (or a Pmosfet, as suggested) to switch a positive supply. Both will allow a very low (e.g. < 50 mV) voltage drop.
Professional Hardware and Electronics Design :: 28.10.2011 10:34 :: FvM :: Replies: 34 :: Views: 2222
why you , don't use a simple totem pole to drive your mosfet?
Power Electronics :: 16.01.2012 17:52 :: goldsmith :: Replies: 5 :: Views: 449
If you're sending continuous pulse at or around 50% duty cycle, then, it is your meter showing you 2.57V (the average voltage), whereas the actual voltage when output=1 is actually 5V. eg. If you're turning RD0 on, waiting 10us, turning RD0 off, waiting 10us, then turning it on again and so on, you have 50% duty cycle and your PIC goes from 0V to 5
Microcontrollers :: 01.02.2012 13:40 :: Tahmid :: Replies: 17 :: Views: 857
how to choose "PNP-npn" mosfet transistors, which operates more than 13.56 MHz and around 3 amp?
what is the right way to look for a transistor with such specific values?
Electromagnetic Design and Simulation :: 09.04.2012 08:35 :: juak :: Replies: 0 :: Views: 439
use uc3844 & mosfet based smps it is constant current & voltage controlled
Power Electronics :: 11.10.2012 13:54 :: pradeep.g.belchada :: Replies: 12 :: Views: 739
2 amp for the LEDs will be really scary for me.....you really need the power LED for my view you need to choose right LED first...... Normal LED can work max up to 100mili-amp so be careful... and second important point is what is the level of voltage i mean voltage level ....I think you can have low voltage like 3 volts but in that cas
Analog Circuit Design :: 09.08.2012 08:26 :: milind.a.kulkarni :: Replies: 2 :: Views: 684
Even if you got the transistor biassing correct, the 1N4007 is not suitable for high frequency rectification, you need a device with faster switching speed.
At first glance, if all you are trying to do is create -18V, why not use an npn transistor (or better still a mosfet) , the same positive rail for the output stage as (...)
Analog Circuit Design :: 10.08.2012 04:21 :: betwixt :: Replies: 4 :: Views: 424
You can have complementary dual transistors (two chips in package) like BC846PN or BC817UPN. transistor arrays with dual polarity (classical part CA3096) are still manufactured for special purpose, but I doubt that they are suitable for your application. Complementary mosfet pairs in a package are quire common.
Analog Circuit Design :: 16.09.2012 05:16 :: FvM :: Replies: 1 :: Views: 286
There are a LOT of ways you can do this; a simple R-C going into a schmitt trigger is one. The output of your schmitt trigger can drive the gate of a mosfet (or the base of a BJT).
Hobby Circuits and Small Projects Problems :: 15.10.2012 07:57 :: barry :: Replies: 5 :: Views: 558
Sorry if this topic was covered already.
I need a transistor (preferentially an npn) for an current source generator. It seems that on the datasheets such VA doesn't appear. Is there a way to calculate it from the other parameters?
I have to choose a npn for a current source with the output impedance in the range of 100 Mohm.
Analog Circuit Design :: 06.11.2012 05:00 :: gianca :: Replies: 1 :: Views: 214
A discrete transistor solution for negative voltage with quite descent performance could be something like this:
By adjusting resistor R7 you can trim the output voltage, but I simulated the circuit, and it gave pretty exactly -15V as it is.
One advantage is, that all components are readily available types and value
Electronic Elementary Questions :: 08.03.2013 16:46 :: ted :: Replies: 9 :: Views: 316