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9v to 3v?

 
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tohu
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PostPosted: Sat Apr 05, 2008 3:29 pm    Post subject: 9v to 3v? Reply with quote

Hello
How to supply 3v tv remote control with 9v battery without consumption current (battery) when the remote control is turned off?
Thanks
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torbjorn



Joined: 07 Jun 2007
Posts: 370
Location: Sweden

PostPosted: Sat Apr 05, 2008 8:12 pm    Post subject: Reply with quote

One possibility is to connect a suitable zener diode in series with the battery. The nearest standard zener voltage is 6,2 V , common types are for example BZX85-C6V2 or BZV79-6V2.

Another possibility is to use a three-leg voltage regulator with extremely low idle current drain. Look at for example www.maxim-ic.com or www.national.com for suitable types. You should NOT try using a standard regulator (i. e. LM317 or any of the 78xx series) as those can draw idle currents of several mA, exhausting a battery in a few days.
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tohu
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PostPosted: Sun Apr 06, 2008 1:40 pm    Post subject: Reply with quote

Hello
Thanks for quick reply.
The using of series of diodes is a good idea , but it takes a big area in the circuit witch is very small .
Is there another method to convert 9v to 3v with transistor ?

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torbjorn



Joined: 07 Jun 2007
Posts: 370
Location: Sweden

PostPosted: Mon Apr 07, 2008 7:20 am    Post subject: Reply with quote

I don't think it is possible to make anything smaller that one single zener diode. And the voltage regulators i mentioned, those are the same size as a SMD transistor.
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