Electronic DC / CC Load
Here you can find out more about my home made 0 to 8 Amp. adjustable / programmable DC load.
The download links for the PCB files etc. are at the bottom of the page. (Beta files! But they work!)
Also check out my YouTube videos showing how I made it.
Parts List:
Q1 = BD139 (NPN Transistor)
R3 = 390 Ohm
R7 = 2K Trimpot
R4 = Jumper wire
R5 = 1 K Ohm
C2 = 220 nF
C5 = 8.2 nF
R11 = 220 K Ohm
R12 = 12 K Ohm
C10 = 220 nF
C11 = 330 nF
C1 = 1 uF
U12 = MAX6241 (Voltage Ref)
NAU7802 = NAU7802 (24-Bit ADC)
C9 = 100 uF (25v)
C8 = 100 uF (25v)
UNLABELED IC = MAX5217 (16-Bit DAC) mounted on a DIP adaptor board
R2 = 5.6K
Q2 = 2N3906 (Small signal PNP Transistor, Pinout should be CBE, but mine was back to front, so I had to rotate it 180 degrees)
R1 = 39K
C4 = 10 pF
C7 = 22uF (25v)
R10 = 680 Ohm
U7 = 16x2 LCD Display
U2 = LT1013 (Dual Opamp)
U22 = LT1013 (Dual Opamp)
C6 = 15 nF
R19 = 20 K Ohm
R18 = 10 K Ohm
R6 = 15 K Ohm
R8 = 2.857 K Ohm
R9 = No component
C3 = 220 nF
R14 = 680 Ohm
R13 = 680 Ohm
R17 = 10 K Ohm
R16 = 10 K Ohm
R15 = 10 K Ohm
U6 = LM35 Temp Sensor, mount on one of the MOSFETS (Pinout, if mounted on the PCB the flat side should be towards the opamps)
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Not labeled on board:
2 Jumper wires
1 uF Capacitor (25v), Between Pin-2 of the ADC and GND
10 uF Capacitor (25v), Between common terminal of R15, R16, R17 and GND
3x IRF540 MOSFTEs
3x 100 nF Capacitor, Between Pin-1 and Pin-3 of the MOSFETs
6x 0.12 Ohm 5W Resistors
Heat Sink L13 x W6,5 x H5 (cm) Or bigger :D :D :D
Fan 12V (80 - 120 mm)
Pin headers Male / Female (80/30 pcs. I think)
Power Supply +12v and -5v, be creative :P
Downloads:
Main PCB - Load_bottom.pdf - Load_top.pdf - Load_silk_mirrored.pdf
PCB Buttons - PCB Overlay - PCB Trace Layer
Firmware V1.40 (Beta) - dc_load_rev140.ino
Firmware V1.30 (Beta) - dc_load_rev130.ino
Enclosure Drawings - load_enclosure.zip
Schematic - Schematic_load.jpg