J
jamie.91
Guest
Re: MXDL
Ahh ok so if i use say 4 diodes and an led ?
Ahh ok so if i use say 4 diodes and an led ?
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IgorT
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Re: MXDL
If you use a LED, 4 diodes could be too much.. Need to measure..
But a CREE LED (or any white LED) will have a Vf of around 3.5V anyway.. So if you use a LED capable of taking high currents, you don't even need a diode in series, but put one or two there anyway. The exact Vf is unimportant, as long as it is in range.
The Vf of the dummy being close to the Vf of the diode only matters, when you use a linear driver, which needs a certain voltage on top of what the load needs.. So there you might want to simulate the right conditions, where the input voltage requirements depend on the output voltage requirements.
With a buck/boost driver, the input voltage doesn't depend on the required output voltage - it just has to be within the input range. And as long as the dummy Vf is within the output range, the current WILL be the same as later with the diode.
If you use a LED, 4 diodes could be too much.. Need to measure..
But a CREE LED (or any white LED) will have a Vf of around 3.5V anyway.. So if you use a LED capable of taking high currents, you don't even need a diode in series, but put one or two there anyway. The exact Vf is unimportant, as long as it is in range.
The Vf of the dummy being close to the Vf of the diode only matters, when you use a linear driver, which needs a certain voltage on top of what the load needs.. So there you might want to simulate the right conditions, where the input voltage requirements depend on the output voltage requirements.
With a buck/boost driver, the input voltage doesn't depend on the required output voltage - it just has to be within the input range. And as long as the dummy Vf is within the output range, the current WILL be the same as later with the diode.
J
jamie.91
Guest
Re: MXDL
ahh i no this is stupid but where should i probe with the DMM with the dummy load ?
ahh i no this is stupid but where should i probe with the DMM with the dummy load ?
IgorT
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Re: MXDL
Well, there are two options.
You can either put the DMM in the current measuring range (2A or more, but for PHRs, 200mA is also good), you have to use another socket for this, so that current can flow THROUGH the DMM, and then you put the DMM BETWEEN the driver and the dummy load.
The other option, which i mentioned before, is to put a 1 Ohm 1 % resistor in series with the dummy load (i make this resistor a part of the dummy load), and use a low voltage measuring range (2000mV = 2V). Then you measure the voltage on both sides of this resistor. Voltage ACROSS a 1 Ohm resistor in mV is the same as the current THROUGH it in mA.
Well, there are two options.
You can either put the DMM in the current measuring range (2A or more, but for PHRs, 200mA is also good), you have to use another socket for this, so that current can flow THROUGH the DMM, and then you put the DMM BETWEEN the driver and the dummy load.
The other option, which i mentioned before, is to put a 1 Ohm 1 % resistor in series with the dummy load (i make this resistor a part of the dummy load), and use a low voltage measuring range (2000mV = 2V). Then you measure the voltage on both sides of this resistor. Voltage ACROSS a 1 Ohm resistor in mV is the same as the current THROUGH it in mA.
J
jamie.91
Guest
Re: MXDL
thanks youre a great help i just hope i can fit it all inside the tiny lil thing lmao
thanks jamie
btw did you find out the colour of the text lol
thanks youre a great help i just hope i can fit it all inside the tiny lil thing lmao
thanks jamie
btw did you find out the colour of the text lol
IgorT
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Re: MXDL
You don't have to fit it all inide the host.. Just the diode in the module with some heatsink, and the driver..
The dummy load is just for driver testing and current setting. Or did i misunderstand you?
I'll go find it now. EDIT: Sent it to your PM..
You don't have to fit it all inide the host.. Just the diode in the module with some heatsink, and the driver..
The dummy load is just for driver testing and current setting. Or did i misunderstand you?
I'll go find it now. EDIT: Sent it to your PM..
J
jamie.91
Guest
Re: MXDL
no i understand i ment i dont know if i can fit the module heatsink and driver thingy in lol its tiny
btw thanks for the colour lol
no i understand i ment i dont know if i can fit the module heatsink and driver thingy in lol its tiny
btw thanks for the colour lol
IgorT
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Re: MXDL
Hehe, sorry, i was just confused from all the talk about the dummy load.. ;D
But the driver is tiny, and if you mount it flat on the depopulated battery contact PCB (use some insulation in between!), you'll be fine.. If you can't use the back of the AixiZ module, don't.. Just use the head, but make sure you have some aluminum around it.
Hehe, sorry, i was just confused from all the talk about the dummy load.. ;D
But the driver is tiny, and if you mount it flat on the depopulated battery contact PCB (use some insulation in between!), you'll be fine.. If you can't use the back of the AixiZ module, don't.. Just use the head, but make sure you have some aluminum around it.
J
jamie.91
Guest
Re: MXDL
yeah im gunna wait till after the holidays when i go back to collage and make a heatsink on the lathe lol just hope we got more material than mild steel lmao
yeah im gunna wait till after the holidays when i go back to collage and make a heatsink on the lathe lol just hope we got more material than mild steel lmao
