電池供電是唯一出路嗎？

zoneaudio

如題.................

billymud

jastudio

比乜嘢用先
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zoneaudio

jastudio 發表於 2014-11-7 01:49
比乜嘢用先
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用電比較小嘅開始啦:）

obee

zoneaudio 發表於 2014-11-7 07:06
用電比較小嘅開始啦:）

聽說電池不是完美, 但我係讀一篇賣CLOCK的文中看到的. 所以唔可以作準.

jastudio

電池當然是不完美的。電池串聯也會有內阻ESR。越高voltage你需要串聯的電池越多，內阻越高，而且後級需要的電流也大很多。這樣，電池供電就變成越不實際。
使用什麼電池也有講究。一般鹼性電池ESR較高。充電電池內阻就低很多。在串聯以增加電壓的同時也可以並聯電池降低內阻。

在低voltage的使用，電池雖然有esr，但比起傳統的LPS 產生既RIPPLE同RFI，還是有相當大的優勢。
所以你看高端的DAC，甚至Preamp等等用15-25V既都有廠家用電池供電,但就算電池供電都會面對voltage drop 嘅問題。

理論上用一些 filter circuit 也可以達到比較接近電池供電的質量，但在參數要求上是要計算的。之後的穩壓板質量也要相當高。不是一般1085/317可以達到，更不要說7915/7912 等等。

如果有看最近一篇SONY HAP-Z1ES 的文章，KK ching 在開發的穩壓供電電路就是朝著超低ripple 及 RFI，接近電池的方向去研究。
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billymud

< abstracted>
NiCD (Nickel-Cadmium) and NiMH (Nickel-Metal Hydride) are two very different types of batteries. Both types must be handled differently from one another in regards to charging and discharging procedures and philosophies.

In general, NiMH batteries cannot handle the high rate of charges or discharges (typically over 1.5-2 amps) that NiCAD batteries can. Many modelers use high rate, peak detection or time-based chargers to charge NiCAD batteries. Such chargers are NOT recommended for NiMH batteries (unless otherwise specified in the charger or battery literature) as they can cause permanent damage to the NiMH cells. Also, NiMH batteries will not perform well in high rate discharge applications, typically providing only a small fraction of the rated capacity in these instances.

NiMH batteries also have approximately twice the self-discharge rate of NiCAD batteries when in an used state. For example, when your radio is off, a 1650mah NiMH battery can discharge itself nearly twice as quickly as a NiCAD battery, typically within one week. Therefore, you must charge your NiMH batteries the night before each use.

jastudio

billymud 發表於 2014-11-7 12:05
< abstracted>
NiCD (Nickel-Cadmium) and NiMH (Nickel-Metal Hydride) are two very different types of  ...

是，充電電池也有分快放電及慢放電。 用在遙控車的便是快放電式。 但是比起鹼性電池，還是快很多。

jastudio

kk_ho 發表於 2014-11-7 13:13
大家要注意題目
電池供電
Pure DC

kk 你一講pure dc就全部死晒。pure dc
任何情況任何loading 都係一條直線。
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