Is this +9V 0 -9V adapter same as a regulated 9v DC adapter found in the market? What about the Amp rating? I guess it would not matter if its a regulated dc adapter?.
Also would the regulated dc adapter will be fine providing 9V even when the voltage drops to 170-180V?
Your 3.2A transformer might have a voltage of 9.4VAC when the load is only 1A and it will be cool.
You could look thru the web for an SMPS with 170v thru 240V input , with the required +/-9Vdc output
I have an adsl modem and i have was just wondering if i can use a battery to make it work. The power rating of my modem is 9V DC and 0.5 A.
Now the question:
1) Do I have to connect a battery providing current exactly 9V, 0.5A?
The reason some of these modems require 9Vac as an input, is because of the RS232 voltage level requirement.
The modem internal diodes half wave rectify the 9Vac to give ~ +9Vdc and ~-9Vdc.
I am one retired from the same BSNL and did lots of servingHi
I am trying to solve a similar issue and needs advice of experts here.
The Chinese modem supplied by the broadband provider BSNL (India) has issues with its AC adapter. If you leave it on for couple of hours it gets very hot and if you leave it on for couple of days, it will burn.
The AC adapter outputs 9V AC and rated at 1 Amps. I replaced the Chinese modem with D-link 502t, recommended by the local supplier. The D-link modem also came with 9V AC and rated at 1A. I suspect the Chinese modem is a copy of the D-link as the web administration is exact the same. However the D-link adapter didn't last for more than couple of weeks.
I think the voltage fluctuates quite frequently and hence cause these adapter to burn. I am looking for a solution to power up my modem, which requires 9V AC 1Amp and can work under voltage ranging between 170V to 240V.
I couldn't find any 9V AC to AC adapter that are regulated. Is there any thing like AC to AC regulated power adapter?
I was thinking of buying a 230V AC to 9V 3.2Amps AC adapter. Will it work with the modem that requires 9V 1Amp AC as input?
The reason I want to go with a higher Amp is so that it does not get hot. Am I thinking right?
Please advice.
Thanks in advance
Why are you talking about a DC adapter? You don't know where inside the modem to connect it.
you can supply 12V regulated DC with a capacity of 1 amp or 1.5 amp. the Huwawei and UTstar modems are HOT
but your concept that the temp growth curve is steep and it would burn is not correct.
BSNL of late is supplying locally developed 12V SMPS adopters of Axium or similar makes. unless faulty, the supply id reasonably good
however your initial quesry whether you could opearte the Modem with12V DC-- YES
it helps you work with lap top even under power failures.
i can tell a simple way, use a manual voltage corrector with a switch. set it to 180 V , connect your modem power supply and leave it in the nights. no problem will comeI was just trying to follow up the suggestion made by all the experts here. I would feel more comfortable, if I don't have to open the modem and your explanation about voltage rise seems good to me.
I am buying the 120V AC to 9V AC (3.1A) adapter from **broken link removed**, which is a reputed company in the UK with high street stores and hence I hope that the adapter is of good quality.
There is another variable voltage 1 Amp AC 2 AC adapter **broken link removed**. Not quite sure which one is better for my use.
i can tell a simple way, use a manual voltage corrector with a switch. set it to 180 V , connect your modem power supply and leave it in the nights. no problem will come
not needed
the modem has an input bridge rectifier
Please tell me the make and model number. i will get you the internal photograph.You don't waste money purchasing components and paying international couriers. At least India is that capable of making a good small power supply.
Thanks a lot. Being a very proud Indian, I am well aware of the how efficiently and cheaply things can be done in India. e.g. the electrician only asked for Rs.100 (£1.5) to open the transformer and redone it.
But until now, it was quite difficult to know what will work? I tried 4 different adapters (in India), each of them costing around Rs.500, but none of them worked.
What is a manual voltage corrector? Is is the same as regulator that we use for fridge? I have tried that, but the adapter got burnt. I know lot of people in Kishanganj, whose adapter got burnt and as BSNL does not supply spare ones (at least in Kishanganj), they had no choice but to buy D-link 502t for Rs.2000.
The modem that we have have got is D-Link 502t and the BSNL supplied is possibly UTstar.
Thanks a lot for your quick response. I hope I will be able to solve the adapter issue. The amount of money and time I have spent on this issue that I am prepared to pay another £10-20, if I can solve this ones and for all.
But so far I am not clear what to do. Will the 9V 3.2A AC adapter will work with these modems?
a manual voltage stabilizer as used on fridge etc, it has an UP or DOWN switch and another rotary switch with 5 steps.
Please have one and keep it in DOWN position wand adjust rotary switch to have 10V output . use this 180 to the adopters etc. i fear that most of your failures are during night times when the voltage reaches high as 275V. these transformers (12V Ac or DC adopters) start cooking their electrolytic caps inside.
exactly !!The manual voltage stabilizer has a manual rotary switch to set the input voltage between 170 to 220 Volt.which gives 220 volt output. I have not seen any of them that gives 10 volt output. Do you mean then plug a 10V adapter to its output? Can you please explain?
Many Thanks
exactly !!
the output would be used to power all your equipment so that night high voltages don't burn the equipments. they are manual stabilizers and are cheap
We had enough discussion on the power subject. neither we can come and live in Canada, nor India or any other country can become Canada or US overnight. Let us find ways to manage the situation. Perhaps more important is equipment survival in the prevailing conditions.Why doesn't your electrical utility company adjust the voltage so it is correct?
Mine does.
No.If your wall adapter outputs 0.5A @ 9V, then a 9V battery connected with the proper polarity to the input power connection of the ADSL modem will work just fine.
No.Now, you want to know how long the battery will last. Well, becuase batteries are rated in milliamp hours and they have a much larger error tolerance, batteries can only be said to be reliable for 70% of their rated life minimum.
So, typical 9V batteries are rated at ~700mAH, dispite what the gentlemen earlier said. if you don't believe me, check the technical specs from energizer and duracell.
So the equation is (current of the battery / current being drained)*0.7 = (700mAH/500mA)*0.7 = 0.98 hours.
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