Voltage regulator question

[johnson]

Just bought a Tahmazo T10 and thinking about how to power it.

Is there such a thing that converts 16.5 volt DC to 12~13 volts DC?

What I am try to do is to use my laptop AC/DC converter (16.5 volts output) with some kind of regulator and drop the output to 12-13 volts to power the T10 so I don't need to bring many adapters when I travel.

[X34]

What is the max voltage the charger can accept?

[johnson]

The spec says 11 to 15 V. Tried last night with my laptop adapter at 16.75V no load, didn't work.

[Super-Hornet]

What is the current consumption of the Charger or how high can it charge the battery?

The easiest voltage regulator will be using LM7812 Voltage regulator.

Since you are using AC adapter, there is another solution is to modify your AC adapter to supply 12V instead but u need electronics (especially power electronics) to do it.

Super-Hornet

[johnson]

Hi Super-Hornet,

The charger will charge at 3 Amp max. I don't want to mod the ac-dc adapter because I still need it for the laptop.

Where can I find any documentations for constructing the circuit diagram? I have given back all my year one electronics knowledge 16 years ago after the exam.....

By the way, got a regulated ac-dc adapter and will use it to power the charger. However, still want to build the voltage regulator for travel use.

Thanks.

[Super-Hornet]

Hmm... That means u need at least 3.xx Ampere. Why? Well, your Charger also need some power also.

So lets assume it is 3.5Ampere. But lets round it off to 4Ampere. Also assume u are going to charge at 3A. If not, let say 1700mAH battery, then u need 1.7A will do.

With that, is your AC adapter can supply at least 3.5A? If yes, then the easiest will be using LM7812 in parallel of 4 pieces. (Or less if u are going to charge less than 3Amp. One piece of LM7812 - Those standard TIP type - can supply up to max of 1Amp.)

U can get it from any website for the characteristic info. U can find the connection also. I think I did post it in this forum before.... just can't remember where is it.

Even u use 4x of LM7812, u might want to tighten it to a heatsink with a tiny fan to cool it down.

Note: Some charger can accept more than 12V without any problem...especially those that has a internal fan for cooling. So, if u calculated that the cost is more than normal charger (Can accept more than 12V), then mind as well get another charger instead.

Super-Hornet

[johnson]

The power supply can output 4.xxA.

So, all i will need is 4 pc of LM7812? Without any resistors, capacitor etc? If that is the case, then very straight forward!!

[Super-Hornet]

As I said before, I post it somewhere before. Check out the history and u will find it. If u search internet, u can find it also.

U need 2 capacitor. That 2 capacitor is to prevent the voltage from oscillating.

No resistor is required.

Super-Hornet