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Origami and Folding

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Flexure Joint

Dial Indicator
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真空管放大

電子管技術,儘管被說為過時的,低效的和有噪音的,仍然是可提供一些耳朵覺得更悅耳的音色,當然是要有好的方法。著手設計並最終構造出管放大器會帶來一些挑戰和危害。有關使用這項技術主要挑戰是稀缺(因此價格昂貴)組件的可用性,危險的高電源電壓,巨大空間去安排特定佈局和構造及組件約束。

為該項目選擇的設計涉及一個端音頻放大器,由電阻輸入組成網絡,驅動器級和輸出級(通常為8個)始終保持歐姆揚聲器負載,至少使用支持性無源元件,用於偏置和耦合職責。 電源電壓由120 /220VAC的雙半波二極管整流器提供升壓電磁變壓器。 雖然有些瑣碎,但這設計提供了高質量的音頻放大器,可以以合理的成本實現。

此配置具有兩個主要功能。 1M電阻器保持從電網到地面的路徑,無論放大器輸入的狀態,防止電位源故障導致驅動管損壞[4]。 在
此外,將12AX7的米勒電容用於與此網絡一起創建低通濾波器
旨在防止HF無線電干擾相加在這個敏感的階段輸入級的米勒電容等於151pF,使用(1)。 請注意,兩個驅動器增益的值(G),則板與柵之間的電容(CPG)為衍生自B部分。

使用這些公式,中頻帶增益(f = 1 kHz)等於為0 .975,對應於0.22 dB的衰減。開始於535 kHz的商業廣播是使用該設計衰減了23.34 dB,證明了消除了商業無線電干擾。 關心必須採取措施以防止HF衰減音頻頻譜的高端,即B中有更詳細的討論。

駕駛員階段驅動器級的設計與電壓有關放大以及線性,以便提供
輸出部分具有較強且相對乾淨的信號。驅動管的選擇是12AX7
普通的小信號管。 負載線分析用於確定此階段的行為。

上面的負載線是決定使用HT = + 300V電源,由[1]推薦,並且183 kOhm的負載電阻,在一定範圍內由[1] [2] [3]推薦。

Spice Models

China HiFi Audio

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300B

Typical classic A valve amplifier designed by HIFIFever (300B) was shown below. It is a relative simple and easy to build system. You may able to modify it to mono block system. Both power supply and amplifier was divided into 2 channel(L & R) in order to drive the speaker independently.

Compare the above circuit with the old design. The value of resistors and capacitors are changed due to the power supply (i.e. Dual power in old design). 6 Nos. of 5.1K Ohm resistors are in parallel in order to spread the loads. There is a good example to build a valve amplifier from parts.

KTAudio 300B
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Hydroponic

Hydroponic is a form of gardening that uses no soil, but instead grows plants in a solution of water and nutrients. Three systems are suitable for beginners: the wick system, the water culture system, and the ebb and flow system. More advanced systems include the nutrient film technique and the aeroponic system. The easiest plants to start with are greens like lettuce, spinach, Swiss chard, and kale; herbs like basil, parsley, oregano, cilantro, and mint; and fruiting plants like tomatoes, strawberries, and hot peppers.

The following vegetables can be grown in the period of time with hydroponic methods.

Vegetable# WeeksFlowers# weeksHerbs# Weeks
Artichoke10-12Ageratum6-8Basil6-8
Broccoli5-7Alyssum8-12Catnip8-12
Brussels Sprouts5-7Batchelor Button4-6Chamomile8-12
Cabbage5-7Calendula6-8Chervil6-8
Cantaloupe3-4Coleus12-14Chives12-14
Cauliflower5-7Dahlia4-6Coriander6-8
Celery7-12Daisy6-8Dill6-8
Chinese Cabbage5-7Fuchsia18-20Feverfew8-12
Collards5-7Godetia4-6Lemon Balm6-8
Cucumbers3-4Impatiens12-14Mint12-14
Eggplant6-8Lobelia12-14Oregano12-14
Kale4-6Marigold5-6Parsley12-14
Leeks10-12Nasturtium4-6Sage6-8
Lettuce5-7Nemesia6-8Savory6-8
Okra2-4Pansy12-14Thyme8-12
Onion10-12Petunia8-12
Pepper8-10Poppy12-14
Pumpkin2-4Snapdragon8-12
Spinach6-8Sweet Pea8-12
Squash3-4Zinnia5-6
Swiss Chard6-8
Tomato6-8
Watermelon5-7
Duration of Grow

Tips for growing plant.

Tips for indoor plant

Tips of easy system

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Toy

Due to the improvement of technology and cultures, doll toy is changed accordingly. The doll were created based on human look figure, cartoon, character of television, robot or super hero of film. Products related to the doll or human figure are relatively more profitable.

Smart Doll – Family Series
Frame of Smart Doll
Japanese Cartoon Character Toy Kit
R2D2 – Model
Iron Man Bust
Iron Man – Figure