Discussion in 'General Electronics Chat' started by jake_cornell318, Nov 5, 2007.

1. ### jake_cornell318 Thread Starter New Member

Nov 5, 2007
2
0
I work for a company that sells numerous products to the public including electronic products.

Today we have had an enquiry as to why the machine operates on 9V's of AC and then 2x 9V Batteries, producing 18V's of DC?

It has been bugging me all day so now I need help!

Cheers
Jake

2. ### beenthere Retired Moderator

Apr 20, 2004
15,815
283
Little hard to answer the question as no description of the product in question is given. Possibly the two 9 volt batteries are in parallel for extra current capability.

3. ### recca02 Senior Member

Apr 2, 2007
1,211
0
there is fair chance if the m/c works at 9 volts then two batteries (connected in a parallel configuration to still give 9 volts not 18 volts which would have been the case if they were connected in series) are only to increase current capability or for that matter the hours the machine can run on battery supply.

4. ### jake_cornell318 Thread Starter New Member

Nov 5, 2007
2
0
Cheers recca02,

Pretty sure that must be the case, well at least thats what the customer will be told because he is just really being picky lol

5. ### recca02 Senior Member

Apr 2, 2007
1,211
0
just be sure not to provide any incorrect information.
both of the above replies were based on assumptions and experiences.
may be you should contact the manufacturer for a better answer.
or maybe u can provide some relevant details so that the members of the forum can help you out further.

6. ### nomurphy AAC Fanatic!

Aug 8, 2005
567
12
Provided that the statement of 18V (two 9V in series) is correct, then it's probably because 9VAC will produce about 12-13VDC. Therefore two 9V batteries can be used to satisfy that condition, whereas one will not (completely ignoring the possible use of a DC-DC boost converter).

Another possibility is that they are used to create a split supply, and the two 9V are not connected in series or parallel, but make +/- 9V.

7. ### recca02 Senior Member

Apr 2, 2007
1,211
0
i completely overlooked that ac part.
thanks for bringing that to attention.