This question already has an answer here:
How much can a power brick safely vary from what the device it's used with expects?
As an example, let's say I have a device that needs an AC=>DC power brick. The device expects 19V/1.58A, but the brick is missing. Now let's say I find a brick where the connector fits the device and is also 19V, but outputs 3.42A. How safe is this likely to be for the device? Will the device only draw the power it needs, or am I likely to blow a capacitor somewhere?
If that latter, this example the brick provides more than twice the current requested. How much closer would have I have to get to be reasonable? How much can voltage vary vs amps? Given different devices likely have more tolerances than others, is there a good rule of thumb to look for to know how much you cheat on matching power brick to device?
While the example does match a real situation, I'm also interested in the general case.