該文章連載於第11期和第12期的《試聽前線》，有配圖。
電容是高傳真度設備裡不可或缺的重要組成部分，將能量儲存在正負電極之間形成的電場中。兩個薄膜狀的電極（通常使用金屬製成）被一層電介質隔開，並折疊或卷起來，就成了薄膜電容。電極的材料有鋁、錫、銅、銀或者合金。電介質可以是任何絕緣的材料，例如空氣、玻璃、陶瓷、雲母、紙、聚脂薄膜、聚苯乙烯、聚丙烯或特氟隆（聚四氟乙烯）。最好的電介質材料是真空，其次是空氣，第三是特氟隆，隨後才是聚酯，聚丙烯，油等材料。
電容的一個重要用途就是信號耦合――通交流隔直流，它使得音樂信號（交流）可以自由通過而直流電壓無法通過。沒有電容是完美的，任何電容在傳輸信號的時候都會有不同程度的信號損耗，特別是非Hi-Fi的電容的信號損耗是很大的。理論上的解決辦法是採用直耦電路來取代耦合電容，但是任何有電子知識的人都知道，直耦電路不僅實施起來困難而且應用範圍有限，很多情況下無法使用直耦電路取代耦合電容。
那麼，另一個解決方案就是努力去尋找最好的耦合電容來降低信號損耗，這就是我們組織這次評論的主旨，我們花費了16個月的時間來聚齊了所有最頂級的21款hi-end電容。
Envision the circuit of the SIT power amplifier
Circuit plan 1
Tamura's PP transformer F-781 can be connected in parallel because two windings of 2.5 kΩ on the primary side are independently drawn out to the terminals, and when connected in parallel, the impedance becomes 1/4 of 625 ohms.
When 8Ω is loaded on the 16Ω terminal on the secondary side, the primary side becomes 312.5Ω, so I tried to draw a load line with this.
In the gate-drain voltage 450V at maximum rating of SIT, the gate-source voltage is generally a 20V, V D -I D towards the characteristic graph V D because it is documented = 600V, equivalent of a voltage It may be strong.
However, since it is an expensive element, I will avoid using it unreasonably.
If the operating point is V D = 180V, I D = 50mA and the load line of 312.5Ω is drawn , V D = 13V, I D = 584mA, and the maximum output is 44.6W at V GS = 0V .
2020.10.4 Get this from Paul Frost, the designer of DAC11001. Write him a mail.
The overview of QA401, USB and DSP section are isolated from DA/AD. TI ISO2401 provides signal isolation, and WE parts provides DC-DC galvanic isolation.
How to Hack the Bandwidth and Sample Rate for Tektronix TDS1000-2000-3000 Series Oscilloscope?
1. Let firmware is V3.39
2. Open Tektronix Web interface
3. Enter the password to unlock
PASSWORD PITBULL
MCONFIG TDS3064B
4. Reboot the Scope, done!
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