You can use any 9v adapter as long as the output amperage is rated higher than the amperage rating of your appliance so yes a 600ma adapter can be used to power a 500ma or 400ma appliance
A device which requires 1000mA at 9 volts in order to operate will not work from an output of 500mA. This output is only half the power requirement of the device.
Your question is confusing, but if you are asking whether you can use a 9V/250 mA adapter to supply a load device rated at 5 V/1000 mA, then the rule is quite straightforward. The adapter's rated output voltage must match that of the intended load, but its rated current must exceed that of the load. So in your example, you cannot use the adapter with the intended load.
Your power adapter is rated up to 30 volts at 1000ma. (1 amp.) If you have a device which only draws 1 milliamp, then it should work with this adapter, as long as the voltage is correct.
Yes, the rating of the adapter is the maximum amount of current allowed to be drawn from it. The adapter you state has a maximum of 1000 mA or 1 amp. If the device draws 700 mA's you will have 300 mA's of spare capacity.
Yes, an adaptor with a capacity of 1250 mA's will run devices that are rated up to and including 1250 mA. Always check that the voltage from the adapter matches the device.
No, because the provided rating of 12volt, 2.7Amp equivalent to 2700 mA (milli amphere) is a much higher as to the adapter said 12volt, 1000 mA (Milli Amphere).
No. Usually it's a -/+ 10% difference. So, a 9v would need at least 7.2 volts or more
yes this will work fine
Assuming the plug fits, and that the polarity is correct it'll work fine. Drawing less amps than the source can deliver isn't a problem, it'd be a bit like filling a glass from a pitcher. Drawing more amps than the source can deliver is what you need to watch out for, that can cause overheating and all sorts of nasty failures.
Yes the voltage is close enough to work. What you have to be cautious about is the milliamp output of the adapter. Make sure that the output of the adapter is higher than the device that plugs into it.
This is a universal adapter a should work.