I have bought this capacity tester:
https://www.aliexpress.com/item/32495202056.html?spm=a2g0s.9042311.0.0.16b64c4dGIMtgC
and I have opened it and found out that it has two of those large green resistors inside.
Now from what I know is that in order to have variable current with resistors you have to connect more or less resistors in series and that the current can't be changed as it's not based on mosfets that can do that.
So, how is it possible?
I have a huge load tester I build from 10 1500w resistors and I have made a fancy relay switch box to turn 1-10 resistors in order to controller only to find out that it's possible with some arduino style thingy and the same resistors I use.
*I have seen about 4 large resistors with a heat sink in there but it's obvious they don't take the actual load as this device is built for constant current of 20A at 72V
https://www.aliexpress.com/item/32495202056.html?spm=a2g0s.9042311.0.0.16b64c4dGIMtgC
and I have opened it and found out that it has two of those large green resistors inside.
Now from what I know is that in order to have variable current with resistors you have to connect more or less resistors in series and that the current can't be changed as it's not based on mosfets that can do that.
So, how is it possible?
I have a huge load tester I build from 10 1500w resistors and I have made a fancy relay switch box to turn 1-10 resistors in order to controller only to find out that it's possible with some arduino style thingy and the same resistors I use.
*I have seen about 4 large resistors with a heat sink in there but it's obvious they don't take the actual load as this device is built for constant current of 20A at 72V