MOSFET Latching Circuit

Thread Starter

Trent-Janak

Joined Feb 12, 2020
8
IMG_4181.JPG
My professor drew us up a MOSFET latching circuit. In this circuit a single button push will turn on the VOUT pin. I redrew what he had and i am trying to understand why this circuit when simulated does not work. Any help is appreciated
 

dl324

Joined Mar 30, 2015
10,055
Welcome to AAC!

You should indicate device polarity on the schematic and give them unique designators (e.g. R1, R2, Q1, Q2).

It would also be helpful if you included supply voltage and MOSFET part numbers so we're able to do a realistic circuit analysis.
 

Thread Starter

Trent-Janak

Joined Feb 12, 2020
8
Supply voltage is 3 volts and the battery i realize is drawn backwards. As far as the polarity and type of FETs is where i am unsure.
 

dl324

Joined Mar 30, 2015
10,055
As far as the polarity and type of FETs is where i am unsure.
There are many types of FETs. You should be more specific. Part numbers would clear things up, but you're the one asking for help and you shouldn't make that any more difficult for us than it has to be.
 

Thread Starter

Trent-Janak

Joined Feb 12, 2020
8
Ok let me go a layer deeper. The specific circuit is for our senior design project, and our professor drew up the circuit as an example of what we could use. I do not know what type of FETs to use, since i do not have any prior experience with them.
 

crutschow

Joined Mar 14, 2008
24,361
Can you use more than 3V?
3V will require a MOSFET with a very low threshold voltage, Vgs(th), of less than 2V maximum.

What polarity MOSFETs did you use (N or P channel)?

How will the latch be turned off once it is latched?
 
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Thread Starter

Trent-Janak

Joined Feb 12, 2020
8
Can you use more than 3V?
3V will require a MOSFET with a very low threshold voltage, Vgs(th), of less than 2V maximum.

What polarity MOSFETs did you use (N or P channel)?

How will the latch be turned off once it is latched?
There is no need for it to be turned off. Basically a single throw switch. And i used on P and one N Fet
 

Thread Starter

Trent-Janak

Joined Feb 12, 2020
8
Which is which?
How did you simulate this, and with what devices?
i simulated it through multisim, but im not sure which is The P and which is the N. This was drawn for me as an example by our advisory prof. I just cant seem to get it to work and he did not explain all of the details
 
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