Hi all, thank you for your help up front - i have been beating my head on my workbench for a couple weeks now. I am new to the electronics world, but I have tried to do as much research as I could.
I have a couple questions;
1: I have a 48 V power supply (12.5 A). Its feeding a number of thermoelectric Peltier plates (see image of schematic), each plate draws 14.4 Vmax and 6.4 Imax. I need the top layer of plates to be colder then the bottom layer, thus why i have two pairs wired in series, then a group of 4 wired in series. By my math using Ohm's law, the resistors I need for the first two pairs is : (14.4 * 2) = 28.8. 48V -28.8V = 19.2V 19.2V / 6.4a = 3Ω ....? right ???
so my understanding is that the first two pairs need a 3Ω resistor. Now, with 48v power supply feeding 12.5amps I connected a 25Ω potentiometer to test this after adjusting it down to around 4 ohms resistance...and I fried my pot. So that made me question if at 1/4 or 1/2 watt resistor will do the job. I tried looking this up in the forums here but could not find a definite answer. Will a 1/2 watt resistor do the job for the current i am putting through it?
Question 2: should I be wiring the first two pairs of plates in parallel instead of in series? I have enough current to supply two disks in parallel, but am not sure if this is an advantage for me or not.
Thanks again for any feedback / suggestions
I have a couple questions;
1: I have a 48 V power supply (12.5 A). Its feeding a number of thermoelectric Peltier plates (see image of schematic), each plate draws 14.4 Vmax and 6.4 Imax. I need the top layer of plates to be colder then the bottom layer, thus why i have two pairs wired in series, then a group of 4 wired in series. By my math using Ohm's law, the resistors I need for the first two pairs is : (14.4 * 2) = 28.8. 48V -28.8V = 19.2V 19.2V / 6.4a = 3Ω ....? right ???
so my understanding is that the first two pairs need a 3Ω resistor. Now, with 48v power supply feeding 12.5amps I connected a 25Ω potentiometer to test this after adjusting it down to around 4 ohms resistance...and I fried my pot. So that made me question if at 1/4 or 1/2 watt resistor will do the job. I tried looking this up in the forums here but could not find a definite answer. Will a 1/2 watt resistor do the job for the current i am putting through it?
Question 2: should I be wiring the first two pairs of plates in parallel instead of in series? I have enough current to supply two disks in parallel, but am not sure if this is an advantage for me or not.
Thanks again for any feedback / suggestions