question

Yes. Your spec is 12V, you have that at 245 mA you have better.

Tom

Yes.

Actually, you're right on target.

Its good to operate at 50% capabilities.

and

the

So it means that the transformer gives 500ma maximum but if the receiver only needs 245ma then only 245ma will be drained by the transformer, right?

By the way, it's better to use 9v in the transformer? Since in this case I have

33,33% and 22,22% respectively for upper and lower voltage limit of operation of the receiver (7-12V dc)?

Thanks for your answers!

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Where did the 245mA number come from?

Not necessarily. At the lower voltage the current will usually be higher. That's why I asked were the 245mA came from. Three digit precision indicates that it's not a "spec" number, rather something measured (as a side note, therefore a "nominal" number). More information please.

Another Usenet free-loader.

Your receiver will draw the current necessary from your supply. You have a good margine of safety. The spec of 7-12 volts indicates that the receiver has it's own regulator. Without seeing the circuit I don't know if it would be better to use 9 volts. Even it would, it would matter very little in this case.

Tom

--- This is sci.electronics.basics so, since you've made a few errors which no one has addressed yet, let's correct them:

1. A receiver doesn't usually have an output current specification, so what you probably mean is that it's rated for 7 to 12VDC in at 245mA max, yes?
2. Transformers don't have DC outputs, so what you're referring to is an AC to DC converter with a regulated output adjustable from 1.5 to 12VDC at 500mA max.
3. It appears you have the input and output spec's somewhat scrambled in that AC inputs are rated in volt-amperes (VA) instead of watts, and output power is rated in watts (W) instead of VA.

Such being the case, it appears that your supply requires an input of 230V 50Hz at 12.5VA and can output from 1.5 to 12VDC at 6W max.

Notice that this output power can only be realized when the output is set at 12VDC, since with an output voltage >= 1.5V and

If the adjustable supply is a switcher, or if it uses a selection of taps on a transformer, AND if the receiver has a linear regulator which accepts the 7-12 VDC, then better overall efficiency may be obtained by setting the supply to a lower value. You save (12-9)*0.245 = 0.74 watts by using 9 VDC.

Go for the green energy star!

Paul

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VDC.

Thanks all of you for the feedback. So, right now I have no doubts that I can use the power adapter. This is the item I want to buy:

Don't know if the receiver has a linear regulator or not, only know what's described in the website.

Btw, for 72 euros considering a 200mw 1.2ghz transmitter + receiver, is a expensive set?

Thanks again!

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given that it's regulated yeah that'll work (as long as you get + on the center pin)

If it's adjustable I'de b incluned to set it to 9V or 7.5V just for extra safety.

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