Can magnets screw up laser sights?

[Flechette]

I have a pistol with a laser sight on it that has worked fine. I got a new holster that has a magnetic clasp on in (the flap is held down with a magnet built into the flap). I had the gun in this holster for awhile and when I took it out to check everything the laser barely had any strength, so I figured that the batteries were dead and made a note to change them the next day. I laid the gun on the table.

However, when I went to swap out batteries the laser worked again! I thought it could be one of those cases of the batteries "recharging" themselves slightly after use. Typically when this happens the laser (or any other battery powered item) will quickly lose power with just a little bit of use. So I kept the laser on for awhile...but it still worked.

So then I decided to repeat the situation by putting the gun back in the holster. If I took it out after a few minutes it worked fine. The next day however laser appeared weak again!

What type of physics or chemistry is going on here? Could the magnetic field be affecting the batteries or perhaps the electronics?

 

[Jack B.]

Make sure the new holster is not turning on the laser when you holster it.

 

[Flechette]

Make sure the new holster is not turning on the laser when you holster it.

I have. I can peek around the edges to see inside. I have also intentionally left the laser on and holstered it and it is very visible (the entire inside glows)

 

[Flechette]

Update:

After taking the laser apart I noticed some of the components. There appear to be two MOSFET (Metal Oxide Semi-conductor Field Effect Transistor) driving the laser. After doing some online research, it appears that a magnetic field can alter the drain current of the MOSFETs:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5038667/

This appears to be leading edge quantum physics stuff: "Therefore, the drain current modulation by the very small on-chip magnetic field for a MOSFET device with single-drain structure remains unexplored."

So my laser sight's batteries may indeed be draining faster than normal due to a magnetic field!

Who knew that guns and quantum physics would have anything to do with each other!

 

[Mal H]

I might believe that if you had left the laser switched on. But, with it switched off and still draining the batteries, the MOSFET theory doesn't stand up.

If you think it is the magnet, test it scientifically. Set the handgun/laser on a table overnight without the holster. Place a strong magnet somewhere near the handgun for one night, and no magnet the next night. See if the magnet affects the laser output using that setup.

Also, what type of battery is being used?

 

[Flechette]

I might believe that if you had left the laser switched on. But, with it switched off and still draining the batteries, the MOSFET theory doesn't stand up.

If you think it is the magnet, test it scientifically. Set the handgun/laser on a table overnight without the holster. Place a strong magnet somewhere near the handgun for one night, and no magnet the next night. See if the magnet affects the laser output using that setup.

Also, what type of battery is being used?

I am using energizer 377/376 1.55 V silver oxide batteries (4 of them).

 

[kcofohio]

The MOSFETs on your laser, acts as a gate, usually waiting for a micro switch to tell it to open. The power is at the MOSFET, not the switch. So, there is a minute amount of energy being used while it waits. Unless your laser has a disconnect switch that separates the battery from the chipboard.
At least that is with my small amount of experience of MOSFETs.

 

[Mal H]

Most handgun laser sights have an activation switch (often turned on by just gripping the gun), and a master on/off switch. Flechette - how are you turning off the laser when you put it away overnight?

 

[Flechette]

Most handgun laser sights have an activation switch (often turned on by just gripping the gun), and a master on/off switch. Flechette - how are you turning off the laser when you put it away overnight?

It has a button switch. Push once it turns on. Push a second time and it turns off.

 

[denton]

I'd think first about dirty switch contacts.

 

[AZAndy]

Who knew that guns and quantum physics would have anything to do with each other!

Oh, everything has to do with quantum physics. For example, I have a Schroedinger revolver-- only way to tell if it's loaded is to take it out of the safe.

 

[Mal H]

Okay, and now you're going to tell me that half the time you take it out it's loaded, and half the time it isn't!

 

[Flechette]

Okay, and now you're going to tell me that half the time you take it out it's loaded, and half the time it isn't!

Actually, it is both loaded and unloaded at the same time...until you look.