水草情迷

請問一個output4.9v 850mA既電話牛駁6支LED電筒得唔得,要並聯定寸聯呢?如果唔得又可以去邊度買隻岩用既電子牛呢?

你唔識計就真係唔好整啦, 尤其是用係魚缸, 就算唔因超載而過熱, 都要小心做防水功夫. 外行唔熟就真係唔好試, 以免因小失大呀!

多謝好意!但我既問題係個output4.9v 850mA既電話牛駁6支LED電筒得唔得(係DC電),AC電我就唔會亂試,請放心

純粹路過，好耐冇見呀泰臣，電既野唔識，可能識既睇漏眼，幫你推一推。

你要講你d led幾大input.

Hi 泰臣

I am not electonic engineer, but can share what I know. First of all, LED is drive by current, not voltage. For superbright LED, it is about 30mA per LED.

Nevertheless, you are using LED flash light, it is probably connected with resistors. Do you know what is the required input voltage? How many batteries required per each flash light and the battery type? For instance, AA (LR6) type batteries, it is about 1.5V per cell. If it required for 3 cells, that menas the input voltage is 4.5V.

If your flash light is design for 3 x AA type batteries, you may use 4.9V input (new battery start from 4.65V). Othereise you need to add resistor to limit the current (or change the resistor inside the flash light). Beware of selecting the suitable resistor (Watt, P=I^2R), or it will overheat.

Regarding the current, if you input source is 850mA, in theory, it can support up to maximun 28 superbright LED. Since there is power consumed from the resistors and wires etc., you are recommend not to connect more than 20 superbright LED (about 70%). Check the number of LED contained inside each flash light.

Finally, connecting in series or parallel depends on the configure on the flash light. If the flash light only need a stable voltage input (like 3 dry cell), connect them in parallel. This will provide the same voltage for each flash light. Or you take out all LED and connect them in series, all LED would be driven by the same current. In this case you need to calculate the required resistor value and power of the resistor.

Hope this is not too difficult for understanding. If there are any incorrect comments, please help to correct it.

Regards

Ivan

Hi~鏍絲兄真係好耐冇見,近來好嗎?

puretung兄~其實唔係LED,係比LED更光的電筒,十蚊支鴨記買的用三粒AAA電,遲D會影相Post上來!(細缸用一流 )

hkyclui兄~首先要多謝你的寶貴意見!但係因為我唔知電筒燈係幾多mA所以無得計 我會用並聯因V唔變+(mAx燈數)試一試 (電筒內已有電阻)

Hi 泰臣

Regarding your flash light, if it is designed for AAA x 3, so you can use your transfomer connecting them in parallel. Now you need to check how many LED has been included in the lamp. If only one is used per flash light, then no problem for connecting 6 flash light. If it is more than 1 per flash light, make sure not connecting more than 20 LED (not flash light).

Regards

Ivan

http://led.linear1.org/led.wiz
for your reference

VI=P