The most simple and most basic type

The most simple and most basic type of power supply filter is a single shunt capacitor
filter, as shown in Figure 3. We saw in the previous lab that the full-wave rectifier produces a full-wave output waveform which is twice that of the frequency of the input supply frequency. We can increase its average DC output level even higher by connecting a suitable filter or smoothing capacitor across the output of the bridge circuit as shown in Figure 3.

The filter capacitor converts the full-wave rippled output of the rectifier into a
smoother DC output voltage. Generally for DC power supply circuits the filter capacitor is an
aluminium electrolytic type that has a capacitance value of 100 µF or more with repeated DC
voltage pulses from the rectifier charging up the capacitor to peak voltage. However, there
are two important parameters to consider when choosing a suitable filter capacitor and these
are its Working Voltage, which must be higher than the no-load output value of the rectifier
and its Capacitance Value, which determines the amount of ripple that will appear
superimposed on top of the DC voltage.EE2-02/3
Too low a capacitance value and the capacitor has little effect on the output
waveform. But if the filter capacitor is sufficiently large enough (parallel capacitors can be
used) and the load current is not too large, the output voltage will be almost as smooth as
pure DC. As a general rule of thumb, we are looking to have a ripple voltage as little as
possible. For example, a typical value is less than 100mV peak to peak for a 10 V DC power
supply (or less than 1%).
The maximum ripple voltage present for a full-wave rectifier circuit is not only
determined by the value of the filter capacitor but by the frequency and load current, and is
given as

One practical and cheaper approach to reduce ripple voltage is to use an off the shelf
3-terminal IC voltage regulator, such as a LM78xx (where "xx" stands for the output voltage
rating) for a positive output voltage or its inverse equivalent the LM79xx for a negative
output voltage which can reduce the ripple by more than 70dB (see datasheet) while
delivering a constant output current of over 1 A. Figure 4 depicts picture, pin diagram, and a
typical circuit of a 12V 3-terminal IC voltage regulator in TO220 case style.

ผลลัพธ์ (ไทย) 1:

The most simple and most basic type of power supply filter is a single shunt capacitorfilter, as shown in Figure 3. We saw in the previous lab that the full-wave rectifier produces a full-wave output waveform which is twice that of the frequency of the input supply frequency. We can increase its average DC output level even higher by connecting a suitable filter or smoothing capacitor across the output of the bridge circuit as shown in Figure 3.The filter capacitor converts the full-wave rippled output of the rectifier into asmoother DC output voltage. Generally for DC power supply circuits the filter capacitor is analuminium electrolytic type that has a capacitance value of 100 µF or more with repeated DCvoltage pulses from the rectifier charging up the capacitor to peak voltage. However, thereare two important parameters to consider when choosing a suitable filter capacitor and theseare its Working Voltage, which must be higher than the no-load output value of the rectifierand its Capacitance Value, which determines the amount of ripple that will appearsuperimposed on top of the DC voltage.EE2-02/3Too low a capacitance value and the capacitor has little effect on the outputwaveform. But if the filter capacitor is sufficiently large enough (parallel capacitors can beused) and the load current is not too large, the output voltage will be almost as smooth aspure DC. As a general rule of thumb, we are looking to have a ripple voltage as little asเป็นไปได้ ตัว ค่าปกติไม่เกิน 100mV สูงสุดไปสูงสุดสำหรับพลังงาน V DC 10อุปทาน (หรือน้อยกว่า 1%)แรงดันไฟฟ้าสูงสุดระลอกปัจจุบันสำหรับวงจร rectifier แบบเต็มคลื่นจะไม่เพียงกำหนด โดยค่า ของตัวเก็บประจุฟิลเตอร์ แต่ โดยความถี่และกระแสโหลด และเป็นได้รับเป็นวิธีปฏิบัติ และราคาถูกหนึ่งเพื่อลดแรงดันกระเพื่อมจะใช้การออกจากชั้นวางเทอร์มินัล 3 IC ควบคุมแรงดันไฟฟ้า เช่น LM78xx ที่ (ที่ "xx" หมายถึงแรงดันขาออกคะแนน) สำหรับเป็นแรงดันไฟฟ้าบวกหรือเทียบเท่าผกผันการ LM79xx สำหรับการลบเอาท์พุทแรงดันไฟฟ้าซึ่งสามารถลดการกระเพื่อมมากกว่า 70dB (ดูแผ่น) ในขณะที่ส่งค่าคงกระแสขาออกของกว่า 1 a.รูปที่ 4 แสดงให้เห็นภาพ pin ไดอะแกรม และวงจรทั่วไปของการควบคุม 12V เทอร์มินัล 3 IC แรงดันไฟฟ้าในกรณี TO220