Mosfet Definition and 215 Threads

Homework Statement Given the following circuit find the input resistance as seen through vo. Homework Equations The Attempt at a Solution To solve this problem I started by drawing the signal equivalent circuit: As we can see the voltage vgs = vi - vo. To find the input resistance I used...

Homework Statement Given the following circuit find the bias point (VDS,IDS). Homework Equations The Attempt at a Solution The first thing I did was find the value of VG, the voltage from the gate of the mosfet to the -VDD source. VG = VDD * R2/(R1+R2) To find the...

Homework Statement Find the internal resistance seen at Vin. Homework Equations The Attempt at a Solution To solve the problem I started by ignoring the condensators and substituting the MOSFET by it's model. This resulted in the following circuit: By applying...

Hi Why do we always bias a mosfet in Saturation mode? Is it becaus gm is more in saturation or is it because gm is more linear in saturation? Thanks Salil

http://www.digikey.com/product-search/en?WT.z_header=search_go&lang=en&site=us&keywords=MOSFET+N-CH+250V+10A+TO-220FM&x=0&y=0 I just recently bought this N-channel MOSFET transistor and when I hook the first pin (gate) to 5V, the second pin (drain) is just an open wire, and the third pin...

Hi I would like some advice on what you think I should use as a passive switch for my NPN or MOSFET transistor. I am trying to PWM pulse with modulate an electromagnet with a 12V 3.6A battery and I want to have a passive switch. I have tried to use photo interrupters in the past but I am not...

Homework Statement Consider a family of logic gates that operate under the static discipline with the following voltage thresholds: VOL = 0.5 V, VIL = 1 V, VOH = 4.5 V, and VIH = 4 V. Using the switch-resistor MOSFET model, design an inverter satisfying the static discipline for the four...

Homework Statement A specific type of MOSFET has V_T = -1\ \rm V. The MOSFET is in the ON state when v_{GS} \geq V_T. The MOSFET is in the OFF state when v_{GS} < V_T. a) Graph the i_{DS} versus v_{GS} characteristics of this MOSFET. Homework Equations The Attempt at a Solution My doubt...

I have a N-ch Mosfet load switch that connects to a WiFi module on a circuit board. When the switch is turned OFF, I still see a voltage of 1.4V at the load. Ckt attached. I decreased the bleed resistor from 1k to 100 ohms. The off voltage decreased to 1.1v. This doesn't happen with other...

So I've been lurking here for a while now, always checking other's solutions but this one has just got me stumped. Skill level: 3rd year electronic circuit design (about the level expected in Sedra & Smith from chapter 3 onwards) Homework Statement For the MOSFET differential amplifier in...

Please help! I have done a lot of pouring over internet searches to try and understand the operation equations for a n type enhancement mode MOSFET for quite some time now. All textbooks limit equations for such devices to currents flowing from drain to source only. But I do know that current...

Hello everyone, I wanted to make some digital circuits with discrete CMOS components but I do not know how to read these MOSFET datasheets properly and I have no idea which models are good for these kinds of projects (for a 3.3V as Vdd and with ground). I know the characteristics of MOSFETs...

Homework Statement A MOSFET has the set of v-I characteristics shown in Fig. P5.5. What are the values of K and VTR? Homework Equations iD=K(VGS-VTR)2 The Attempt at a Solution I have looked in the book and all of the example problems give VTR, but it doesn't show how to actually...

are there any power MOSFET switches that are largely commercially available in the market today? with more than blocking voltage 120 volts at OFF state, ability to conduct more than 30 amperes when in ON state, controling load of over 2500 watts? and in the cost of at least 40 dollars?

How can I calculate how fast I can switch the mosfet? I have the 8 kohm pull up so I think that impacts my charging discharging time? But how do I go abotu calculating it.

Hi, I don't understand pinch-off in MOSFETS. I have two big issues: 1. VDS is pointing from drain to source, so the voltage works in the horizontal plane.VGS on the other hand,is in the vertical plane. So how they can cooperate? How does increasing VDS till VGS - VTh get you in...

Hey guys could you help me out , so I have built this simple smps project that i needed to the multivibrator part works great frequency is stable square wave but then I have these power mosfets IRFP460 , now the multivibrator has two output each 180 opposite to the other I use each of these...

Hello All, I just finished a college course on electronic circuits (opamps, mosfets, bjts, etc) and I'm trying to put some of that knowledge towards designing a basic MOSFET amplifier circuit. Right now I'm at the stage of selecting DC biasing points and I'm having a bit of difficulty...

Hey I have a thing that confuses me. I have a mosfet that has to drive a transformer in pulsed regime. Now I have a multivibrator that gives out 100khz square wave signal and the amplitude of the signal is let's say 30 volts but the mosfet is 330v DC to the Drain and source goes to the primary...

A simple and quick question please clear this up. Let's say I have a 350v rated power n channel mosfet , how much of positive voltage do i have to apply to the gate to fully open the mosfet? I know this varies from type of transistor and so but the average? i am just getting mixed up some...

Hi, I have built some stuff before mainly amplifiers and some power supply modules, tell me what you think of this. I want to ask is it possible to have a series lc circuit that is powered from the rectified + rail through a resistor that gives me the correct voltage and transorb that would make...

Does anyone have some recommendations for MOSFET's that can be used for high frequency low current applications? The ones I found are for high current applications but my application only requires at max 20mA. Thank You.

Homework Statement No actual problem statement. I'm just having trouble understanding what is happening during the depletion and inversion stages. See the attached picture. During the depletion stage, what does it mean by "immobile acceptor ions?" Homework Equations None The...

I'm still not very confident in analyzing circuits. Here's what I know: 1) v_o=v_IN - v_T 2) id=k/2*(v_IN-v_T)^2 3) v_o=v_S-(k/2)(v_IN-v_T)^2*RS 4) v_o = v_S-id*Rs iDS = v_o/RS The answer I chose in the photo was based off of other online discussions. I'm very confused and don't have the...

Hi, i want to design a heat sink for following mosfet http://au.element14.com/vishay-formerly-i-r/irfp360pbf/mosfet-n-400v-23a-to-247ac/dp/8649359 its technical data sheet is provided here http://www.irf.com/product-info/datasheets/data/irfp360.pdf i am not sure how to design it...by...

Hi everyone, I am trying to learn about circuits from some slides I obtained and I am stuck on a slide. Here is a screenshot of it (it is in German): http://i.imgur.com/HCtWF.png It says: Example: Illustration of maximum achievable amplification of a MOSFET with the use of the...

I need to make a large voltage, possibly to make a spark across a 0.05mm gap or at least to make a very large voltage across a resistor. I need this to be triggered digitally by a micro-controller. I was thinking of setting up an inductor and a power MOSFET, but I don't know if this will...

In an N-channel mosfet, for example, can the roles of the Drain and Source be reversed such that the FET turns on with positive VGD? Will this threshold be the same as the specified one for VGS?

So apparently there are two types of Vth for a MOSFET http://www.sdram-technology.info/threshold-voltage-measurement.html How can I tell the saturation apart from linear? Right now I am simulating a voltage sweep (on the Gate) of a transistor and the sim results give a saturation and a linear...

how do you change the frequency in a circuit using a MOSFET?

Homework Statement Homework Equations values in part (a) and (b) which i had found: gm = 2.2mS ro = 25kΩ Rin = 1MΩ Rout = 446.43Ω Av = 0.99 The Attempt at a Solution all that i know is that when they refer to pinch off region, it is referring to the saturation region...

I have been working on some music electronics, I got this on the web and I don't understand how the clipping circuit with germanium diode work. 151334[/ATTACH]"] The part in question is the enhancement mode MOSFET IRF510 with the 1N34 diode. It is a clipping circuit common in distortion box...

Hi, Can you please let me know how does the attached circuit work? Vh and Vl are inputs ; Vbn and Vbp are outputs. Thanks in advance.

hello everyone, I am designing Single ended primary inductor cell(SEPIC) converter. the objective is to get output voltage from 5V to 20V and 1 A current when we change the duty cycle of the pulse supplied to gate of MOSFET. when i simulated the circuit in proteus MOSFET is unable to turn off...

HI, I am very confused how to connect my bulk of MOSes in my circuitary. NMOS bulk should be connected to lower potential and PMOS bulk should be connected to higher potential of the system. Moreover, Source and Drain are interchangeable and so whichever is at higher potential acts as drain...

I've currently using a signal generator into the gate of a MOSFET to switch an inductive load. I've built a 555 circuit to replicate the signal generator output (TTL 5V 192kHz). When I connect this to the gate, the power supply driving the MOSFET limits the current and shuts itself down...

Good Morning, I'm new to electronics. I'm looking for an optocoupler to drive a Mosfet (IRF840). The load is a 220VDC 2A LED lights. It should work like a switch. Can I use an optocoupler with transistor output? I think I can't because the max voltage between emittor and collector is 70V and...

Hi, I would like to ask hot o determine switching frequency for a MOSFET by looking at the datasheet. Most of the datasheet don't provide such information but they provide the following times: Switching on time [ton], raise time [tr], falling time [tf], switch off time [toff] example...

Ignition Coil Won't Spark from Mosfet but DOES spark By Hand? HELP!? I'm trying to get an ignition coil to create sparks running it with a Mosfet powered by a 555 timer. The Mosfet is definitely switching. I checked it with resistor, ampmeter, and o-scope. Everything is behaving predictably...

What is the difference between multi-fin trigate MOSFET and multi-fin FinFET? Why Trigate performs better?

Hey guys and gals. I am curious as to whether this circuit will protect the FET. I am specifically concerned with ceramic capacitor C14. I used the HBM 150pF 330Ohm 25kV with a worst case capacitor bias of 70% (ie: at the ESD voltage, the capacitance will drop to only 30% of it's rated value) to...

Why the voltage drop across the insulator is linear in the band diagram of a MOSFET??

Hello all. It's been awhile since I took a circuits class, so any help would be greatly appreciated. Thanks in advance. Homework Statement See attachment for circuit drawing and question. Homework Equations OHM's law? V=IR Idiode = Io - id The Attempt at a Solution I've tried...

guys i had spend more times on how to determine the drain current exactly using the prefer equations , but I failed i think the problem comes from extracting the correct Kp (constant of mosfet) any one can put here in details how to calculating + writing the procedures&equations step by step...

long time when i had tried more on how to extracting Kn from mosfet datasheet finally i found it; i datasheet look at gfs parameter with its details lets take IRF510 ---------------------------------------------------------- gfs------------ 1.3 ----------- @3.4 A ----------- simens...

I'm encounter a problem in biasing mosfet irf510 ; please someone answer me... why i can not get an output over than 3V i had using voltage divider to bias at 4.5V (R1=R2=100K) ; Vdd=9V; Vout should be = 3V .. Rd=600 OHM where Id=10mA the problem here that i do not like to use Rs as source...

Homework Statement I must admit I'm a noob when it comes to Analog Circuits, I need help! it actually took me a while to understand what the problem is and how to explain it to you guys. I'm given the attached exercise and I'm asked to calculate voltage gain and output resistance, both with...

Homework Statement Derive an expression for the equivalent small-signal conductance Geq (or resistance Req). Homework Equations Geq = \frac{i_t}{v_t} vt = vg vs = 0 vd = -vt The Attempt at a Solution Attachment - EE HW 2 I drew the small-signal circuit, from what I...

Yohoho. I've got an N-MOSFET driving some relays that control the 'Run' circuit in a vehicle. If a FET fails, these relays must not cut off power while the car is running. The FET's I'm using are ON Semi's NCV8402. They are pretty heavy duty as it is, but I want to implement some sort of...

I have the following circuit wired up on a protoboard. The datasheet for the BSS138 MOSFET is here. I'm puzzled regarding what I'm seeing happen with this circuit - when I apply 3.3V at the gate resistor, the MOSFET turns on fully and I see 3mV at the output. This, of course, is expected...