I recently purchased a Hanmatek HM305 power supply. It has some nice features but it has an "undocumented feature" I don't understand. Perhaps someone knows a little more about this.
It works fine stand alone, but when I connect other devices like a scope or lap top to the circuit I building/testing I've had a lot of issues damaging components. I thought at first I might have an issue with the 120vac source to the power supply being wired wrong, but it is fine. So I took a DVM and measure the DC output of the power supply to the earth ground of the 120vac source and what I found was surprising. With neg lead of the DVM on earth ground I get -10dc on the neg output post of the power supply. (the power supply was set at 10v). And, I get a solid 0v on the pos output post of the power supply. So it seems the pos output of the power supply is tied to ground. Not an issue when the power supply is floating on an isolated circuit, but when combined with other equipment its a problem. I did the same measurements on my old analog DC power supply and did not measure any voltage on either post.
Has anyone out there had an issue like this? Am I doing something wrong?
Smoking mad.......
Jim
It works fine stand alone, but when I connect other devices like a scope or lap top to the circuit I building/testing I've had a lot of issues damaging components. I thought at first I might have an issue with the 120vac source to the power supply being wired wrong, but it is fine. So I took a DVM and measure the DC output of the power supply to the earth ground of the 120vac source and what I found was surprising. With neg lead of the DVM on earth ground I get -10dc on the neg output post of the power supply. (the power supply was set at 10v). And, I get a solid 0v on the pos output post of the power supply. So it seems the pos output of the power supply is tied to ground. Not an issue when the power supply is floating on an isolated circuit, but when combined with other equipment its a problem. I did the same measurements on my old analog DC power supply and did not measure any voltage on either post.
Has anyone out there had an issue like this? Am I doing something wrong?
Smoking mad.......
Jim