PCC
Flashlight Enthusiast
Quantum Tunneling Composites, which will only be referred to as QTCs from now on, are small rubber-like pads that conduct electricity, varying its resistance based on how much it is compressed. When static, they provide infinite resistance. As pressure is applied it conducts with lesser and lesser resistance until they reach very little or no resistance. I have not tried measuring this. They can handle up to about 10A of current, though no voltage rating was given for that figure. They come in 3mm X 3mm X 1mm squares that look like small patches of rubber bicycle inner tubing that has been cut into tiny squares.
The Kuku 38DD light uses a QTC to offer infinitely variable brightness levels. I believe there are other lights that use QTCs in them as well.
I really prefer multi-mode lights over single-mode lights because I believe that multi-mode lights are more practical because you can vary the brightness based on the need.
I purchased 100 pieces of QTCs to experiment with and they arrived earlier this past week (please don't PM me asking to sell you any as I fully expect to use all of them and may even need to order more down the road). At first I tried taking the tailcaps off of a few flashlights, putting a QTC on the negative end of the battery, then placing a screwdriver across the bare aluminum of the flashlight contact, pressing down on the QTC to see if I can vary the light's output. For the most part, I was able to vary the output from quite a few of my lights so I know that most of them will work with a QTC mod.
The one light that I have that currently has a QTC in it is a SS Quark Preon ReVO. I removed the rear spring and replaced it with a small piece of aluminum that I turned on my lathe. I reinstalled the rubber retaining ring/spring and dropped a QTC into the body tube, making sure that it sat in the middle, on top of the aluminum piece. I then dropped a battery in the body tube and screwed down the head. What I have now is a light that will come on gently (as opposed to just instantaneously turning on) that I can turn down to moonlight mode or less as needed. I can still turn the light on/off/on to switch modes and I get them, but, I can then slowly loosen the head and the light will dim down. Really cool. It's not perfect as the rubber ring on the negative end of the body and the rubber ring on the head have some torque from the twisting action and this usually means that the light will settle into a brighter or dimmer output after a few seconds, depending on which direction the head was twisted to get to the desired output. Still, it's really nice to be able to use this light in a moonlight mode that makes my Quark 123 Tactical on moonlight mode seem bright. I can get full brightness for whichever mode I'm in by simply tightening the head. The thing is that the circuit board on the light is fighting me when trying to set a low mode and it won't fire the circuit until it's got enough lack of resistance to get about 80% of the power needed to get the normal low mode so it will always start off brighter than I need it to be and needs to be turned down from there. It's been mentioned that the greater stiffness of the QTC setup may eventually lead to a damaged circuit board on the head of my ReVO, and this is duly noted, but, so far so good.
I have a Streamlight BatonLite that I've modified with a Sandwich Shop Mad Max Lite driver and SSC P4 U-bin LED powered by 2 AAA batteries. I removed the tailcap contact assembly and pulled the spring away from the metal washer that makes contact with the end of the body tube to turn on the light. I placed a QTC in between the spring and the washer and reassembled the light. This setup is much easier to set a super low output mode than the ReVO. I can slowly twist the tailcap until the light turns on so dimly that I can barely see any hotspot at all at 3 feet in a completely dark room. From there I can ramp it up to full brightness. I do, occasionally, get a weird quirk where the light will dim before getting brighter, however. I'm not sure why this is. I do worry about rubbing through the QTC because the twisting action is causing the QTC to rub against the end of the body tube.
Other lights that I have tried the QTC on and have acknowledged that it works with them:
Anything direct-drive
Rebel MagLED 2D and 3D
Nite Ize 1-Watt and large dome PR flange drop-ins
Nite Ize 3-LED Mini-Mag drop-in
Sandwich Shop Mad Max Plus and Lite drivers
DatiLED's toroid Joule Thief
ThruNite 3-9V XM-L P60 drop-in
Dereelight SST-50 P60 drop-in pill
SureFire L1 (current version)
SureFire KL4 (120 lumen version)
Quark 123 Tactical
Quark MiNi 123
Quark Preon ReVO
In all cases, I tested by placing the QTC at the tail cap and shorting to the QTC and then applying pressure to the QTC and then observing whether or not I can vary the brightness or not and if it is a smooth transition.
Lights that don't seem to like having the resistance changed at the tailcap:
Solarforce Masterpiece Pro-1 head
Sandwich Shop Shark Buck 2A
SureFire G2X Pro (ramps up but only comes on in low mode, will not switch to high no matter what)
In the case of the Solarforce MPP-1 and the SS Shark Buck 2A, they are either on or off and didn't really dim when applying pressure to the QTC.
I'll post pictures of this stuff later.
The Kuku 38DD light uses a QTC to offer infinitely variable brightness levels. I believe there are other lights that use QTCs in them as well.
I really prefer multi-mode lights over single-mode lights because I believe that multi-mode lights are more practical because you can vary the brightness based on the need.
I purchased 100 pieces of QTCs to experiment with and they arrived earlier this past week (please don't PM me asking to sell you any as I fully expect to use all of them and may even need to order more down the road). At first I tried taking the tailcaps off of a few flashlights, putting a QTC on the negative end of the battery, then placing a screwdriver across the bare aluminum of the flashlight contact, pressing down on the QTC to see if I can vary the light's output. For the most part, I was able to vary the output from quite a few of my lights so I know that most of them will work with a QTC mod.
The one light that I have that currently has a QTC in it is a SS Quark Preon ReVO. I removed the rear spring and replaced it with a small piece of aluminum that I turned on my lathe. I reinstalled the rubber retaining ring/spring and dropped a QTC into the body tube, making sure that it sat in the middle, on top of the aluminum piece. I then dropped a battery in the body tube and screwed down the head. What I have now is a light that will come on gently (as opposed to just instantaneously turning on) that I can turn down to moonlight mode or less as needed. I can still turn the light on/off/on to switch modes and I get them, but, I can then slowly loosen the head and the light will dim down. Really cool. It's not perfect as the rubber ring on the negative end of the body and the rubber ring on the head have some torque from the twisting action and this usually means that the light will settle into a brighter or dimmer output after a few seconds, depending on which direction the head was twisted to get to the desired output. Still, it's really nice to be able to use this light in a moonlight mode that makes my Quark 123 Tactical on moonlight mode seem bright. I can get full brightness for whichever mode I'm in by simply tightening the head. The thing is that the circuit board on the light is fighting me when trying to set a low mode and it won't fire the circuit until it's got enough lack of resistance to get about 80% of the power needed to get the normal low mode so it will always start off brighter than I need it to be and needs to be turned down from there. It's been mentioned that the greater stiffness of the QTC setup may eventually lead to a damaged circuit board on the head of my ReVO, and this is duly noted, but, so far so good.
I have a Streamlight BatonLite that I've modified with a Sandwich Shop Mad Max Lite driver and SSC P4 U-bin LED powered by 2 AAA batteries. I removed the tailcap contact assembly and pulled the spring away from the metal washer that makes contact with the end of the body tube to turn on the light. I placed a QTC in between the spring and the washer and reassembled the light. This setup is much easier to set a super low output mode than the ReVO. I can slowly twist the tailcap until the light turns on so dimly that I can barely see any hotspot at all at 3 feet in a completely dark room. From there I can ramp it up to full brightness. I do, occasionally, get a weird quirk where the light will dim before getting brighter, however. I'm not sure why this is. I do worry about rubbing through the QTC because the twisting action is causing the QTC to rub against the end of the body tube.
Other lights that I have tried the QTC on and have acknowledged that it works with them:
Anything direct-drive
Rebel MagLED 2D and 3D
Nite Ize 1-Watt and large dome PR flange drop-ins
Nite Ize 3-LED Mini-Mag drop-in
Sandwich Shop Mad Max Plus and Lite drivers
DatiLED's toroid Joule Thief
ThruNite 3-9V XM-L P60 drop-in
Dereelight SST-50 P60 drop-in pill
SureFire L1 (current version)
SureFire KL4 (120 lumen version)
Quark 123 Tactical
Quark MiNi 123
Quark Preon ReVO
In all cases, I tested by placing the QTC at the tail cap and shorting to the QTC and then applying pressure to the QTC and then observing whether or not I can vary the brightness or not and if it is a smooth transition.
Lights that don't seem to like having the resistance changed at the tailcap:
Solarforce Masterpiece Pro-1 head
Sandwich Shop Shark Buck 2A
SureFire G2X Pro (ramps up but only comes on in low mode, will not switch to high no matter what)
In the case of the Solarforce MPP-1 and the SS Shark Buck 2A, they are either on or off and didn't really dim when applying pressure to the QTC.
I'll post pictures of this stuff later.
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