Determining mosfet type
Use the circuit bellow to determine mosfet type if you happen to not know of it
the circuit gives the mosfet a heat stress depending on bias and heatsink used
keep the test brief especially if you use a small or no heatsink this will also
depend on id current and vds of mosfet, dont use huge current that will heat up
the mosfet very quckly and keep the dissipation and temp of the mosfet within spec
use a low voltage ps 12-20v with medium current up to 2A depending on mosfet
if vds start decreasing 2-3v (switchoff ps) mosfet is vertical type
if vds start increases 2-3v (switchoff ps) mosfet is lateral type
cheers
Use the circuit bellow to determine mosfet type if you happen to not know of it
the circuit gives the mosfet a heat stress depending on bias and heatsink used
keep the test brief especially if you use a small or no heatsink this will also
depend on id current and vds of mosfet, dont use huge current that will heat up
the mosfet very quckly and keep the dissipation and temp of the mosfet within spec
use a low voltage ps 12-20v with medium current up to 2A depending on mosfet
if vds start decreasing 2-3v (switchoff ps) mosfet is vertical type
if vds start increases 2-3v (switchoff ps) mosfet is lateral type
cheers
Attachments
There are really very few lateral MOSFET types, most can be identified by other means, threshold voltage amongst them. The threshold voltage inflection point from positive to negative tempco occurs at about 100-200mA, so feeding a MOSFET with D connectd to G a constant 200mA current, and measuring D+G to S voltage (threshold) variation should be enough to determine what you are dealing with, if the threshold voltage magnitude itself, the case or the markings were not.
Hi,
now that you have all had a go at winding each other up, can I ask my question again but rephrased?
Are all low power Mosfets of the lateral type?
If not, then it appears that Master's method would offer an alternative way of identifying them.
Certainly by the time you get to power Mosfets, they are available in both V & L types and Master's method has been shown to work.
& Yes, I will always be a novice and proud of the fact I am able to continue learning although somewhat slowly.
now that you have all had a go at winding each other up, can I ask my question again but rephrased?
Are all low power Mosfets of the lateral type?
If not, then it appears that Master's method would offer an alternative way of identifying them.
Certainly by the time you get to power Mosfets, they are available in both V & L types and Master's method has been shown to work.
& Yes, I will always be a novice and proud of the fact I am able to continue learning although somewhat slowly.
Supporting Andrew's case a little more, yes I would like to know if TO92 cased devices are always lateral, as if they can be either vertical or lateral this test could be useful.
For MOSFETs in bigger cases this test is not necessary because all you need to do is check the pinout: GDS with D case is vertical, GSD with S case is lateral.
For MOSFETs in bigger cases this test is not necessary because all you need to do is check the pinout: GDS with D case is vertical, GSD with S case is lateral.
richie00boy -
For MOSFETs in bigger cases this test is not necessary because all you need to do is check the pinout: GDS with D case is vertical, GSD with S case is lateral.
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hahaha mate excuse me what are you telling me, i gave you
this great concept of identifiyng any mosfet, and youre telling
me that you prefer coded package stuff
jacco vermeulen -
George,
you're a fun guy, but sometimes you remind me of Donk in Crocodile Dundee.
Those who are familiar with Mosfets know how to differentiate a vertical from a lateral type. So your post is directed to the ones who are a novice related to Mosfets, not necessarily means they are retards.
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jacco i see your point i shared my way, what is yours
who is novice lets see
kind regards
For MOSFETs in bigger cases this test is not necessary because all you need to do is check the pinout: GDS with D case is vertical, GSD with S case is lateral.
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hahaha mate excuse me what are you telling me, i gave you
this great concept of identifiyng any mosfet, and youre telling
me that you prefer coded package stuff
jacco vermeulen -
George,
you're a fun guy, but sometimes you remind me of Donk in Crocodile Dundee.
Those who are familiar with Mosfets know how to differentiate a vertical from a lateral type. So your post is directed to the ones who are a novice related to Mosfets, not necessarily means they are retards.
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jacco i see your point i shared my way, what is yours
who is novice lets see
kind regards
mastertech, I wasn't knocking your method - as it turns out it seems useful for identifying TO92 case devices as Jacco points out they can come in either flavour. However, if you would rather mess about with a rig than look at a datasheet and check the pinout that is just your way of working I guess 
I don't think you can determine MOSFET pinouts of totally unknown devices, with a common meter all that easily. So you need to know the pinout of the device to do the rig test. I am happy to be corrected should I have missed some evidence
I don't think you can determine MOSFET pinouts of totally unknown devices, with a common meter all that easily. So you need to know the pinout of the device to do the rig test. I am happy to be corrected should I have missed some evidence
Added bonus:
for people like me with bad eyesight it is often difficult to read the markings on a TO92 casing, sounds familiar ?
I'm night blind, even with reading glasses i can't read the marking on a TO220 IRF device in the evening.
Quite often, delivered bags of items contain a faulty device. Inspecting and identifying each one at delivery is very time consuming, checking before soldering is easier and gives absolute certainty.
For completeness: the diode check works only once, the gate of a fet is charged after the measurement and needs to be de-charged before it can be checked again.
for people like me with bad eyesight it is often difficult to read the markings on a TO92 casing, sounds familiar ?
I'm night blind, even with reading glasses i can't read the marking on a TO220 IRF device in the evening.
Quite often, delivered bags of items contain a faulty device. Inspecting and identifying each one at delivery is very time consuming, checking before soldering is easier and gives absolute certainty.
For completeness: the diode check works only once, the gate of a fet is charged after the measurement and needs to be de-charged before it can be checked again.
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