110 AC power supply and ACC Driver

[klamerus]

Hi. I'm a total newbie and trying to understand, so any help is appreciated. If I get any of the many offered laser module / ACC driver / 110V power adapter, am I likely to be safe using household power? Or are the irregularities (spikes) going to kill the driver and diode? Same question but 10KW generac generator power vs grid? Switch from one to the other? Is there anything I can do to reduce risk (if there is any)? surge protector, voltage regulator, or anything that is reasonable and low cost?

Many thanks.

 

[diachi]

Hi. I'm a total newbie and trying to understand, so any help is appreciated. If I get any of the many offered laser module / ACC driver / 110V power adapter, am I likely to be safe using household power? Or are the irregularities (spikes) going to kill the driver and diode? Same question but 10KW generac generator power vs grid? Switch from one to the other? Is there anything I can do to reduce risk (if there is any)? surge protector, voltage regulator, or anything that is reasonable and low cost?

Many thanks.

The 110VAC adapter converts the AC mains in your house to low voltage DC for the driver. The diode driver regulates current to the diode. It'll be fine.

 

[klamerus]

Thanks. I figured they sell a lot, it should be OK, but reading all the posts about the sensitivity of the diodes to current overload, mostly, I wanted to make sure.

 

[paul1598419]

I have many lab lasers that run off 110 AC household current. They are all fine as the power supply only provides DC to the driver, as diachi said, and it controls the current to the pump diode or laser diode. If you were running a laser at the time that lightening struck your line, it would likely destroy the power supply, but the laser is still far removed from the PS.

 

[Benm]

It does depend a bit on the power supply really. If you get a switching power supply I'd recommend using one that connects mains ground through to negative out.

There are a lot of switchmode power supplies that have a capacitor between output and input. This capacitor serves to reduce radio interference, and normally is no problem in applications like charging a phone or powering some random device.

You can check for this issue using any multimeter really, just measure AC voltage between the output of the power supply and a known good ground (on your wall outlet, perhaps on something like a metal water pipe if you don't have -any- grounded sockets).

It should read zero if there is no such capacitor present, otherwise it will read a significant voltage (often about half mains). This voltage may seem dangerous, but it isn't because the reactance from the capacitor is so high it will hardly push any current - at least not for a human touching the output and something grounded.

In europe we have 230V mains and the 'leakage' from such capacitors can run up to 1 mA or so - even enough to feel a slight (harmless) tingle if you touch the output and a grounded object at the same time.

The problem could be that a laser diode may not handle that situation too well: It's AC, and when you connect it such that it's somewhat grounded (like through your hands holding it) it could damage the diode when in reverse voltage direction.

Best way to avoid this completely is using a mains power supply with an oldfashioned (heave) 60 Hz transformer it in that completely isolates the mains input from the output, usually with a compliance voltage of 4 kV.

 

[klamerus]

OMG, Benm, you are causing me to exercise brain cells I haven't used since college physics, almost 40 years ago. And it hurts. But I like to understand and you made me do some research and I am finding it interesting. Since the power source is sold with the laser, I am going to go with the idea that the ACC is adequately protective and not producing an inherently counterproductive AC. I was more concerned with power surges in the grid.

But, since you mentioned it, are you talking about a ripple (new word) passed through from the mains (new word) at 50-60 Hz, or an AC from the switching transformer? And the capacitor of concern would be located where in the path from mains to rectifier to switch to transformer to output? Not important to my decision making, but idle curiosity so don't feel a need to reply or provide detail unless you just want to. Though I have no practical electronic experience, I find the theory interesting (again). Thanks