New dummy load PCBs are on the way

I’ve changed a few things, got rid of the P-CH mosfets and added basic remote control capability using (0-5V) signals. Chances to fry this one are considerably lower. All semiconductor parts that get hot are now mounted to the heatsink, and the power resistors will never see more than 0.625W each.

If it works as desired, this will most likely be the final version of this project.

As usual, left-over circuit boards will be available in exchange for a bit of monetary compensation (and shipping costs of course). This time I have decided to do yet another DIY kit experiment, so there will be a limited number (5) of full DIY kits available as well. This is strictly a one-time offer. As all design files are available, people shouldn’t have any trouble with reproduction.

As usual (again…), I only charge for parts and actual costs I’ve had. I’m not trying to rip anybody off. If prices appear to be high, then this is caused by at least 2 facts: a) I only use quality parts that last, b) economies of scale. I don’t order 1000s of parts, so I don’t get the lowest price.

Specs:

• Maximum input voltage: 20V
• Input current: 0-5A
• Power: 20W continuous (depends on heatsink)
• Runs with a 9V battery

Features:

• Sturdy reverse polarity protection
• Current calibration with a 25-turn trimmer
• 10-turn wire-wound pot for current adjustment
• Binding posts for easy DUT / multimeter connection
• Remote controllable with 0-5V signals (in/out)
• Output signals clamped to 5V with Zener diodes
• Remote/hand control selectable using a jumper
• Power LED + on/off switch

Schematic and all design files.

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