Filters
The pulsations or ripple of the DC voltage can be remove with the proper filter. There are two components used for filtering: a capacitor is used to filter the voltage and an inductor or choke to filter the current.
When a capacitor is used as a filter, it is connected in parallel with the output of power supply, Figure 8-4. Assume that the rectifier or power supply produces an output voltage which has a peak value of 20 volts.
As the voltage rises to its peak value of 20 volts, the capacitor charges to 20 volts also. When the DC waveform tries to drop back toward zero, the line voltage becomes less than the 20 volts the capacitor has been charged to. Therefore, the capacitor discharges back into the line in an effort to keep the voltage from decreasing in value.
When a choke coil is used as a filter, it is connected in series with the output of the rectifier, Figure 8-5. When the current begins to rise from zero toward its peak value, a magnetic field is created around the choke coil. As the current reaches its peak value, the magnetic field does also. They decrease from their peak value back toward zero in the same way. As the magnetic field collapses around the choke coil it induces a current back into the coil. This induced current flows in the same direction as the circuit current. Therefore it aids the circuit current by trying to keep a continuous current flow throughout the circuit.
There are various ways to connect capacitors and chokes into a circuit for filtering. A power supply designed for low power application may use a single capacitor filter. A common filtering arrangement is the “∏”filter. It get its name because it resembles the Greek letter “∏”, Figure8-6.
Power suppliers designed to deliver a large current generally use a choke input filter, Figure 8-7. Choke input means that the choke is connected ahead of the capacitor in reference to the rectifier. This is generally done to keep the surge of current down when the power is turned on.
過濾器
直流電壓的波動(dòng)或紋波可以用適當(dāng)?shù)臑V波器去除。有兩個(gè)組件：一個(gè)用于濾波的電容器是用于過濾的電壓和電感或嗆濾波器的電流。
當(dāng)電容器作為一個(gè)過濾器，它是接在電源輸出，圖8-4。假定整流器或電源產(chǎn)生一個(gè)輸出電壓有20伏的峰值。
當(dāng)電壓上升到20伏的峰值，電容充電至20伏特也。當(dāng)直流波形試圖降回零，線電壓低于20伏的電容被充電到。因此，該電容放電回線在努力保持電壓下降值。
當(dāng)一個(gè)扼流圈作為一個(gè)過濾器，它是連接在整流器的輸出序列，圖8-5。當(dāng)電流開始上升，從零到峰值，磁場是在扼流圈了。當(dāng)電流達(dá)到峰值，磁場也。他們從他們的峰值減少回零以同樣的方式。作為磁場的崩潰在扼流線圈，它誘導(dǎo)電流進(jìn)入線圈。這種感應(yīng)的電流在同一方向流動(dòng)的電流。因此，艾滋病的短路電流，試圖在整個(gè)電路保持連續(xù)的電流。
有各種不同的方法連接電容器和電抗器為電路的濾波。電源的低功耗設(shè)計(jì)，應(yīng)用程序可以使用一個(gè)單一的電容濾波器。一個(gè)常見的過濾裝置是“∏”過濾器。它得名是因?yàn)樗愃朴谙ＥD字母“∏”，figure8-6。
電力供應(yīng)商設(shè)計(jì)提供大電流一般采用節(jié)流輸入濾波器，圖8-7。扼流圈輸入意味著扼流圈連接在電容器中的參考整流器。這通常是保持電流沖擊下打開電源時(shí)。
的直流電壓的脈動(dòng)或紋波可以除去用適當(dāng)?shù)倪^濾器。有用于過濾兩部分組成：一個(gè)電容器用于過濾的電壓和電感器或電抗器進(jìn)行過濾的電流。
當(dāng)電容器被用作過濾器，它是連接在與電源的輸出端，如圖8-4平行。假定該整流器或電源產(chǎn)生一個(gè)輸出電壓，其具有20伏的峰值。
隨著電壓升高到20伏，電容器充電到20伏也其峰值。當(dāng)直流波形試圖回落到零，線電壓小于20伏的電容被充電到。因此，電容器放電回線，以努力保持電壓的降低中的值。
當(dāng)扼流線圈用作過濾器，它被串聯(lián)連接在所述整流器的輸出端，如圖8-5所示。當(dāng)電流開始從零上升到朝向其峰值，一個(gè)磁場被扼流線圈周圍產(chǎn)生。當(dāng)電流達(dá)到其峰值，磁場的作用也。他們從峰值下降走回零以同樣的方式。作為磁場扼流線圈圍繞其折疊感應(yīng)出電流返回到線圈。該感應(yīng)電流流在相同的方向上的電路的電流。因此，它有助于電路的電流通過試圖保持整個(gè)電路的連續(xù)電流流動(dòng)。
有多種方法來連接電容器和電抗器轉(zhuǎn)化為一個(gè)濾波電路。專為低功耗應(yīng)用的電源可以使用一個(gè)單一的電容濾波。一個(gè)常見的過濾安排是“ Π ”過濾器。因?yàn)樗愃朴谙ＥD字母“ Π ” ，圖8-2 6它得到它的名字。
旨在提供一個(gè)大電流電源供應(yīng)商一般采用扼流圈輸入濾波器，如圖8-7 。扼流圈輸入裝置，該扼流圈被連接前面的電容器在參考整流器的。通常這是保持電流的浪涌下來時(shí)，接通電源。