MOSFET TESTING

Started by Jessica Shaw in sci.electronics.basics6 years ago 4 replies

Hi, I am trying to test the following power MOSFET using digital multimeter. http://www.fairchildsemi.com/ds/FD%2FFDL100N50F.pdf I am...

Hi, I am trying to test the following power MOSFET using digital multimeter. http://www.fairchildsemi.com/ds/FD%2FFDL100N50F.pdf I am using the following way to do this http://in.answers.yahoo.com/question/index?qid=20061126230136AA6Blij But this MOSFET is showing anything. Its a new part. I tried another MOSFET (IRF540) and the test worked fine. I think that FDL100N50F has large...


mosfet driver needed for logic-level mosfets?

Started by Anonymous in sci.electronics.basics1 year ago 43 replies

Hello, I've discovered logic-level mosfets, and am using an Arduino to drive a small 12VDC (about an amp or so) pump motor with PWM, using an...

Hello, I've discovered logic-level mosfets, and am using an Arduino to drive a small 12VDC (about an amp or so) pump motor with PWM, using an IRLZ34N as the power mosfet. Would a mosfet-driver be recommended to switch that mosfet on and off more quickly? Or is a logic-level mosfet already designed to efficiently turn on and off with the weak logic level signal? Thanks, Michael


MOSFET: N- or P-, enhance or deplete?

Started by Bob Engelhardt in sci.electronics.basics1 year ago 35 replies

Here's really basic question for s.e.BASICS: I want to use a MOSFET to control a load, via a switch. The tricky part is that I need load...

Here's really basic question for s.e.BASICS: I want to use a MOSFET to control a load, via a switch. The tricky part is that I need load current when the switch is open and no current when the switch is closed. What I am confused about is what type of MOSFET to use, and its orientation in the circuit (S & D connected which way?) + | ...


Mosfet as a 12V Switch (and opto)

Started by Prog...@gmail.com in sci.electronics.basics11 years ago 8 replies

I've been stuck on this for awhile. I've got a MOSFET that is not behaving the way I expect. I was hoping it would act similar to the...

I've been stuck on this for awhile. I've got a MOSFET that is not behaving the way I expect. I was hoping it would act similar to the following animation where source to drain is controlled by the gate: http://www-g.eng.cam.ac.uk/mmg/teaching/linearcircuits/mosfet.html But when applying 12V between the source and the drain, my load (a light) slowly illuminates as if a capacitor is power...


Basic static electricity question

Started by M. Hamed in sci.electronics.basics4 years ago 8 replies

Let's say I walk over the carpet and get charged to 10KV. Then I touch a MOSFET. Is it fair to assume that the MOSFET won't be damaged unless...

Let's say I walk over the carpet and get charged to 10KV. Then I touch a MOSFET. Is it fair to assume that the MOSFET won't be damaged unless it has a path to ground?


DC motor pwm, mosfet barbecue, etc.

Started by Anonymous in sci.electronics.basics6 years ago 12 replies

Hi, I built a pwm circuit (200 Hz switching frequency) using 12V as a supply, also using around 12V to the gate of an IRF530 mosfet. I tested...

Hi, I built a pwm circuit (200 Hz switching frequency) using 12V as a supply, also using around 12V to the gate of an IRF530 mosfet. I tested it with an automotive turn signal light (about 1 amp) and it worked just fine (without a heat sink on the mosfet). I then tried using it to control a 12V tire inflator/compressor (about 4 amps). The inflator operated fine, but then when I felt the mo...


Driving a big LED with a MOSFET

Started by fungus in sci.electronics.basics6 years ago 40 replies

I'm trying to drive a big LED (3W) with a MOSFET. Eventually I want to drive it with an Arduino but so far I'm failing to get the right numbers...

I'm trying to drive a big LED (3W) with a MOSFET. Eventually I want to drive it with an Arduino but so far I'm failing to get the right numbers in my test circuit. My test circuit is like this: +5 | [R1] (8 Ohms) | D G -[R2]--- JUMPER S | LED | GND I can connect the jumper cable to +5V or ground and it switches on/off as expected. My MOSFET is one of th...


75332P MOSFET drain connected to which battery terminal?

Started by John Doe in sci.electronics.basics7 years ago 11 replies

I have a 75332P MOSFET on a cordless drill controller heatsink. I guess it's part of a pulse width modulator. The drain (flange) connects...

I have a 75332P MOSFET on a cordless drill controller heatsink. I guess it's part of a pulse width modulator. The drain (flange) connects directly to one of the battery terminals. Does the MOSFET drain go directly to the battery minus/ground terminal? Or does it go to the battery plus terminal? Thanks. -- My application... I'm desperately trying to develop a better inline ...


HF design approach

Started by lerameur in sci.electronics.basics5 years ago 16 replies

Hello to all, I am designing an amplifier for frequencies between 500khz to 5Mhz. (+/-40V= ) a couple of watts. I am a newbie to HF frequencies...

Hello to all, I am designing an amplifier for frequencies between 500khz to 5Mhz. (+/-40V= ) a couple of watts. I am a newbie to HF frequencies , but I would like to know what is the best= amplifier technique for these frequencies.=20 At first I wanted a pushed and pull mosfet driven by a mosfet driver, but t= he more I am looking the more i'm confused. I've seen some expensive specia= liz...


mosfet? transistor? hexfet?

Started by Anonymous in sci.electronics.basics12 years ago 11 replies

When would one use a transistor? mosfet? hexfet? Basically looking into PWM switching of medium-sized DC motors (12V, ~5A or so). Which...

When would one use a transistor? mosfet? hexfet? Basically looking into PWM switching of medium-sized DC motors (12V, ~5A or so). Which should I use...? A beefy transistor like a TIP36C? Or a hexfet like IRLZ34NPBF (98c at Mouser)? Thanks... Michael


Driving higher voltages with p-type MOSFET

Started by Anonymous in sci.electronics.basics6 years ago 28 replies

Hi guys: I'd like to control a 24Vdc load by sourcing with a p-type power MOSFET. I'= m driving the gate directly from a mictrocontroller that...

Hi guys: I'd like to control a 24Vdc load by sourcing with a p-type power MOSFET. I'= m driving the gate directly from a mictrocontroller that uses +5 and ground= . The problem is that I need +24 and +19. I looked into "high voltage level= translators", but they have been discontinued or are a non-stock item. Is there a simple, standard way that this is done? Thanks for any replies. ...


Does current flow when Vds is negative in power mosfets?

Started by kyujin in sci.electronics.basics12 years ago 3 replies

I'm asking this question, because of the diode in the MOSFET models. I know these diodes are to prevent spikes, but looking at it, makes...

I'm asking this question, because of the diode in the MOSFET models. I know these diodes are to prevent spikes, but looking at it, makes me wonder. If Vsource > Vdrain by say 20Volts, can a current flow through the MOSFET even if the gate is not turned on? This would be a reverse current I guess. And if it does, how much? Normally there is a limit to Vds. but I'm wondering about the negativ


MOSFET as a switch and Rds(on)

Started by eliben in sci.electronics.basics9 years ago 3 replies

Hello, I'm having a slight confusion over what Rds(on) means for a MOSFET. In the book it says that Rds(on) is the resistance (Vds / Ids) in...

Hello, I'm having a slight confusion over what Rds(on) means for a MOSFET. In the book it says that Rds(on) is the resistance (Vds / Ids) in the linear (triode) region. After the FET enters saturation, the resistance obviously changes as the current stays the same for increasing voltage. However, people I ask say that they only use FETs for switching (i.e. either cutoff or saturation)...


Optically Coupled MOSFet ??

Started by Jim Thompson in sci.electronics.basics4 years ago 1 reply

Does anyone make an optically coupled MOSFet, Ron around 25 Ohms? All I can find are relay equivalent devices with loads of capacitance. ...

Does anyone make an optically coupled MOSFet, Ron around 25 Ohms? All I can find are relay equivalent devices with loads of capacitance. ...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | ...


mosfet as switch

Started by lerameur in sci.electronics.basics10 years ago 28 replies

hi, I have two 12v batteries which I am hooking up in parallel using a mechanical switch (via the ground). I am attempting to swap the...

hi, I have two 12v batteries which I am hooking up in parallel using a mechanical switch (via the ground). I am attempting to swap the mechanical switch for a mosfet so I can control them from a distance. I tried to model in pspice but this is harder then I imagine. I tried it experimentally, but when I hook up a iRFz44 , the batteries stays in parallel no matter the voltage in the base. ...


What does "high side" MOSFET driver mean ?

Started by Daku in sci.electronics.basics8 years ago 3 replies

Not being a power electronics person, could some electronics guru please explain the term "high side" MOSFET driver. Thanks in advance.

Not being a power electronics person, could some electronics guru please explain the term "high side" MOSFET driver. Thanks in advance.


MOSFET switch - sanity check

Started by Bob Engelhardt in sci.electronics.basics2 months ago 8 replies

I have a Milwaukee 12v variable speed tool with a bad control board. Rather than replace the board, I'm planning to just use a switch for...

I have a Milwaukee 12v variable speed tool with a bad control board. Rather than replace the board, I'm planning to just use a switch for single (full) speed. But the switches that I have & will fit are AC only. So, I'm thinking that I'll use the switch to control a MOSFET that will do the heavy lifting. I just want to make sure that I'm not missing anything. The plan: + ______...


Mosfet motor driver circuit advice

Started by Anonymous in sci.electronics.basics11 years ago 10 replies

Hello, An old project that I'd been working on is that of an electric fishing Kontiki. I have a circuit that I think will work O.K. but I hope...

Hello, An old project that I'd been working on is that of an electric fishing Kontiki. I have a circuit that I think will work O.K. but I hope that someone could take a look at it and point out any glaring mistakes. In particular the mosfet motor driver circuit is of concern to me. http://www.geocities.com/talionis.geo/Temp/temp.html The servo retract button and timeset reed switch are...


MOSFET switching an inductive, high-frequency load

Started by Don Gilmore in sci.electronics.basics5 years ago 8 replies

Guys: I'm an ME working on a project where I must switch voltage to a small coil = on and off at a fairly high frequency (around 25 kHz) with...

Guys: I'm an ME working on a project where I must switch voltage to a small coil = on and off at a fairly high frequency (around 25 kHz) with a MOSFET transis= tor. The DC resistance of the coil is very low (about 1 ohm), but the impe= dance is much higher because of the frequency (about 100 ohms). I'm switch= ing 24 Vdc. Should I specify the max. pulsed current of the transistor based...


Creating sparks with a mosfet and ignition coil

Started by Anonymous in sci.electronics.basics4 years ago 29 replies

I would like to generate a series of ~1000 volt sparks continuously, for several hours, using a spare automotive ignition coil I have lying...

I would like to generate a series of ~1000 volt sparks continuously, for several hours, using a spare automotive ignition coil I have lying around. I found this 555 circuit online: http://www.sci-experiments.com/HighVoltagePulser/ My questions: (1) Is a 500-volt MOSFET really necessary? Would a 100-volt IRF530 work alright without frying? (2) Does the 0.1 uF, 250V capacitor take the ...