relay device
Army is using similar relay devices to increase voltage in some old night vision mobile systems.The problem there is heating and looses on contact switching, since coil is fast switched off and on, the force pressing contacts to each other is not the biggest possible and small resistance can be big problem if high current passing through since power dissipation is increasing with square of current.
Maybe the most interesting formula for you it time constant, which showing a voltage across coil in relation to time. School teaching us that it is Q but in real it is time relation so T = L/R.(L = inductance,R= DC resistance)
Another force working against you is Back EMF which will heat your contact even more, but with T formula you can calculate time when it start rising up , then you can set the proper clocking to be faster....With proper timing you can catch even back EMF, just need to be sure switch the storing accumulator on before EMF is rising up, otherwise you will destroy your semiconductor.Back EMF taking just small fractal of second, but energy stored in that short time is crazy big and sure big enough to destroy any switching semiconductors.I have tried to build some relay self switching ballast for lamp, but the efficiency was really poor because of increasing of frequency and then a poor contacting.
PS to all who just smiling: is better to start with something mechanical and simple, as post many stupid post as i saw on this forum.Always so funny to see people here posting some pictures of devices which light some leds or other stupid things and become a big advisers for others even i can see that even don't have ideas about basic components like L or C ....
To find how electricity works, we need at first to understand how nature react,if we do something.building some devices without understanding that have no meaning.I think if people here dont have idea about basic components then no meaning to try copy don smith or other devices.
If some people want just light a led, is a better way as use high voltage...
Originally posted by crazysailormon
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Maybe the most interesting formula for you it time constant, which showing a voltage across coil in relation to time. School teaching us that it is Q but in real it is time relation so T = L/R.(L = inductance,R= DC resistance)
Another force working against you is Back EMF which will heat your contact even more, but with T formula you can calculate time when it start rising up , then you can set the proper clocking to be faster....With proper timing you can catch even back EMF, just need to be sure switch the storing accumulator on before EMF is rising up, otherwise you will destroy your semiconductor.Back EMF taking just small fractal of second, but energy stored in that short time is crazy big and sure big enough to destroy any switching semiconductors.I have tried to build some relay self switching ballast for lamp, but the efficiency was really poor because of increasing of frequency and then a poor contacting.
PS to all who just smiling: is better to start with something mechanical and simple, as post many stupid post as i saw on this forum.Always so funny to see people here posting some pictures of devices which light some leds or other stupid things and become a big advisers for others even i can see that even don't have ideas about basic components like L or C ....
To find how electricity works, we need at first to understand how nature react,if we do something.building some devices without understanding that have no meaning.I think if people here dont have idea about basic components then no meaning to try copy don smith or other devices.
If some people want just light a led, is a better way as use high voltage...
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