Trigger Schmitt: Me kana da shi Da Kuma Yadda Ake Amfani Da ita

فیلڈ: Karkashin Kuliya da Dukkana

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Mai Schmitt Trigger shi ne?

Mai Schmitt Trigger shi ne comparator circuit da hysteresis domin samun fadada positive feedback zuwa noninverting input ta comparator ko differential amplifier. Mai Schmitt Trigger yana amfani da biyu masu input different threshold voltage level don bincika noise a cikin input signal. Aksi daga wannan dual-threshold ana sani a matsayin hysteresis.

An gina mai Schmitt Trigger a shekarar 1934 a kan American scientist Otto H Schmitt.

Comparator na musamman yana da kawai threshold signal. Kuma yana ci gaba da threshold signal da input signal. Amma, idan input signal yana da noise, zai iya tabbatar da output signal. a schmitt trigger.png

A cikin bayanan, saboda noise a wurareen A da B, input signal (V1) ya kawo level da reference signal (V2). A wannan lokacin, V1 yana da kyau V2 kuma output yana da kadan.

Saboda haka, output ta comparator yana tabbatar da noise a cikin input signal. Kuma comparator ba su ji magancewa noise ba.

Kalmomin “trigger” a cikin sunan “Schmitt Trigger” tana nuna cewa output yana daya har sai hingga input yana canzawa kafin “trigger” wanda za a yi girma.

Mai Schmitt Trigger yana yi aiki kamar?

Mai Schmitt trigger yana ba da amsa masu daidaito saboda input signal yana da noise. Yana amfani da biyu masu threshold voltages; kafuwa ita ce upper threshold voltage (VUT) kuma tafin ita ce lower threshold voltage (VLT).

Output ta Schmitt trigger yana da kadan har sai hingga input signal yana kawo VUT. Idan input signal yana kawo wannan limit VUT, output signal ta Schmitt trigger yana da kadan har sai hingga input signal yana da kyau level da VLT.

Ina bukata in fahimta aiki ta Schmitt trigger ta hanyar misal. A nan zan iya haɗa cewa initial input yana da zero.

Effekta na gishiri a cikin Schmitt Trigger

A nan, muna kawo shiga cewa alamun sakiya na farko ta shi zero kuma yana zama daidai saboda haka da aka nuna a cikin wannan rubutu.

Alamun sakiya na Schmitt trigger ta shi low har zuwa lokacin A. A lokacin A, alamun sakiya ta shi ya karewar da takarda mai yawa (VUT) kuma ta shi ne alamun sakiya mai yawa.

Alamun sakiya mai yawa ta shi har zuwa lokacin B. A lokacin B, alamun sakiya ta shi ya karewar da takarda mai kadan. Kuma haka ta shi ne alamun sakiya low.

Kuma karrin, a lokacin C, idan alamun sakiya ta shi ya karewar da takarda mai yawa, alamun sakiya ta shi ne mai yawa.

A cikin hakan, muna iya duba cewa alamun sakiya ta shi ta da gishiri. Amma ba gishiri ba ta shi ne alamun sakiya.

Circuit na Schmitt Trigger

Circuit na Schmitt trigger ta yi amfani da feedback mai kyau. Saboda haka, wani circuit tana ake kira regenerative comparator circuit. Circuit na Schmitt Trigger zai iya kula da fadada Op-Amp da Transistor. Kuma tana dace da;

Op-amp based Schmitt trigger
Transistor based Schmitt trigger

Op-Amp based Schmitt Trigger

Circuit na Schmitt trigger zai iya kula da Op-Amp a baya biyu. Idan alamun sakiya ta shi an kofar da inverting point na Op-Amp, ana kiran Inverting Schmitt Trigger. Amma idan alamun sakiya ta shi an kofar da non-inverting point na Op-Amp, ana kiran Non-inverting Schmitt Trigger.

Inverting Schmitt Trigger

A nan da shihiyar Schmitt na wannan nau'in, an kara aiki a cikin terminal na inverting ta op-amp. Kuma an kara feedback mai kyau daga output zuwa input.

Yanzu, za a iya fahimtar yadda wannan circuit ya haɗa. A matsayin A, tsari ce V kuma aiki masu (input voltage) ce Vin. Idan aiki masu Vin yana fi V, output na circuit zai kasance low. Kuma idan aiki masu Vin yana ƙarin da V, output na circuit zai kasance high.

$V_{in} > V \quad V_{out} = V_L$

$V_{in} < V \quad V_{out} = V_H$

Yanzu, za a tafi magana V.

An kara Kirchhoff’s Current Law (KCL),

$\frac{V-0}{R_1} + \frac{V-V_{out}}{R_2} = 0$

$\frac{V}{R_1} + \frac{V}{R_2} - \frac{V_{out}}{R_2} = 0$

$V(\frac{1}{R_1} + \frac{1}{R_2}) = \frac{V_{out}}{R_2}$

$V (\frac{R_1 + R_2}{R_1 R_2}) = \frac{V_{out}}{R_2}$

$V = \frac{R_1}{R_1 + R_2} \times V_{out}$

A nan, za a sani cewa aiki na Schmitt trigger yana nuna ta haka. A wannan yanayin,

$V_{out} = V_H \quad and \quad V=V_1$

Saboda haka, daga likitancin da aka bayar a kan yanzu;

$V_1 = \frac{R_1}{R_1 + R_2} \times V_{H}$

Idan alamun da aka gina ya fi shi da V1, karamin Schmitt trigger za a zama low. Saboda haka, V1 ita ce tsari na babban sauki (VUT).

$V_{UT} = \frac{R_1}{R_1 + R_2} \times V_{H}$

Karamin ya zama low har zuwa idan alamun da aka gina yana fi shi da V. idan karamin Schmitt trigger ya zama low, a wannan halin,

$V_{out} = V_L \quad and \quad V=V_2$

$V_2 = \frac{R_1}{R_1 + R_2} \times V_{L}$

A halin, l'output yake da zama ta fiye har zuwa lokacin da siffar mulkin shiga kawai ya fi kan V2. Saboda haka, ana san V2 a matsayin tsari na kadan (VLT)).

$V_{LT} = \frac{R_1}{R_1 + R_2} \times V_{L}$

Non-Inverting Schmitt Trigger

A cikin Non-Inverting Schmitt Trigger, an yi siffar mulki a terminal na non-inverting na Op-Amp. Kuma an yi positive feedback daga output zuwa input. Terminal na inverting na Op-Amp an konektawa a ground terminal. Cikakken abuwar Non-Inverting Schmitt Trigger shine kamar hakan.

A cikin wannan circuit, za a fiye output na Schmitt trigger idan voltage V yana da yiwuwa da zero. Kuma za a kadan output idan voltage V yana da yiwuwa da zero.

$V>0 , V_{out} = V_H$

$V<0 , V_{out} = V_L$

A nan, za aiki da kyau kan kungiyar V. Don haka, za a yi KCL a wannan node.

$\frac{V-V_{in}}{R_1} + \frac{V-V_{out}}{R_2} = 0$

$\frac{V}{R_1} - \frac{V_{in}}{R_1} + \frac{V}{R_2} - \frac{V_{out}}{R_2} = 0$

$V \left(\frac{R_1 + R_2}{R_1 R_2} \right) = \frac{V_{in}}{R_1} + \frac{V_{out}}{R_2}$

$V = \frac{R_2}{R_1 + R_2} V_{in} + \frac{R_1}{R_1 + R_2} V_{out}$

A halin da ake cewa fadada Op-Amp yana da karkashin. Saboda haka, fadada Schmitt trigger yana da VL. Kuma V yana da V1.

A cikin wannan yanayi,

$V_{out} = V_L \quad and \quad V = V_1$

Daga wannan ta hanyar,

$V_1 = \frac{R_2}{R_1 + R_2} V_{in} + \frac{R_1}{R_1 + R_2} V_{L}$

Idan kuma aikin V1 yana da muhimmanci, a fagen bayanu za a fi shi. A nan,

$\frac{R_2}{R_1 + R_2} V_{in} > - \frac{R_1}{R_1 + R_2} V_{L}$

$V_{in} > -\frac{R_1}{R_2} V_L$

Idan wannan maida a tabbatar, a fagen bayanu za a fi shi. saboda haka, wannan tarihi ya ba da muhimmin tsari na aiki (VUT).

$V_{UT} = - \frac{R_1}{R_2} V_L$

Tumma saka cewa a fagen bayanu na Schmitt trigger yana da muhimmanci. Kuma aikin V yana da muhimmanci, V2.

$V_{out} = V_H \quad and \quad V = V_2$

Daga zahiri na tsari V.

$V2 = \frac{R_2}{R_1 + R_2} V_{in} + \frac{R_1}{R_1 + R_2} V_{H}$

Zahiri na Schmitt trigger zai aiki da yake khiɗa idan tsari V2 ya fi kwallon zero. A cikin wannan yanayi,

$\frac{R_2}{R_1 + R_2} V_{in} < - \frac{R_1}{R_1 + R_2} V_{H}$

$\[ V_{in} < -\frac{R_1}{R_2} V_H$

Tushen da yadda ake kawo ma'ana ta hanyar tushen tsari (VLT).

$V_{LT} = -\frac{R_1}{R_2} V_H$

Schmitt Trigger Daga Tushen Tsari

Za a iya gina cikin Schmitt trigger na bincike da tushen tsari biyu. Tushen tsarin Schmitt trigger daga tushen tsari ya ba a cikin cikin tushen tsari.

Vin = ci gaba da tsari
Vref = Tsari mai ban sha'a = 5V

Za a iya neman, a wakar, ci gaba da tsari Vin ita ce zero. An kawo ci gaba da tsari a kan tushen tsari T1. Saboda haka, a wannan halin, tushen tsari T1 take yi a yankin cut-off kuma ita ce ba a yi amfani da shi.

Va da Vb suna da tsari masu nodu. An kawo tsari mai ban sha'a 5V. Saboda haka, za a iya kula tsari Va da Vb da hanyar siffar tsari mai ban sha'a.

An kwa Vb da aka bayar zuwa babban transistor T2. Kuma yana ɗauke 1.98V. Saboda haka, transistor T2 ya zama ta yi aiki. Kuma saboda haka, fitaccen Schmitt trigger ya zama tsoho. Yadda ake ƙara da shi a cikin emmita ya ɗauke 0.7V. Saboda haka, ɗauken voltage na babban transistor ya ɗauke 1.28V.

Emmitan transistor T2 an haɗa da emmitan transistor T1. Saboda haka, duka biyu na transistor sun yi aiki a sama ɗauken 1.28V.

Yana nufin cewa transistor T1 za a yi aiki idan ɗauken voltage na input ya ɗauke 0.7V da 1.28V ko kuma mafi ɗauken 1.98V (1.28V + 0.7V).

A nan, muna zama ɗauken voltage na input mafi ɗauken 1.98V, kuma transistor T1 ya faru a yi aiki. Wannan ya sa ƙara da shi a cikin babban transistor T2 kuma ya zama transistor T2 ya ƙara. Kuma saboda haka, fitaccen Schmitt trigger ya zama jerin.

Voltage na input ya faru a ƙare. Transistor T1 ya ƙara idan ɗauken voltage na input ya ɗauke 0.7V da ɗauken 1.98V, kuma yana ɗauke 1.28V. A nan, transistor T2 ya samu ɗauken voltage na ƙarin, kuma ya faru a yi aiki. Wannan ya sa fitaccen Schmitt trigger ya zama tsoho.

Saboda haka, a nan, muna da biyu na mafagallata, mafagallata tsofi da ɗauken 1.28V da mafagallata jerin da ɗauken 1.98V.

Schmitt Trigger Oscillator

Schmitt Trigger zai iya amfani a matsayin oscil l ator tare da a haɗa da single RC integrated circuit. Diagramma na tsarin Schmitt trigger oscillator yana ɗauke a cikin takarda ta hanyar.

Har da dutsin aiki yana wuce tsohon karamin rauta. Kuma zafi na tsawon karamin rauta yana cikin hakan da R, C, da kuma wurin da Schmitt Trigger ya haɗa.

$f = \frac{k}{RC}$

Idan k ita ce sabbin da take da bayan 0.2 zuwa 1.

CMOS Schmitt Trigger

Dutsin aiki na iya gina tsohon karamin rauta mafi yawan aiki yana ba da tsohon karamin rauta mai girma. Misali, idan tsohon karamin rauta mai girma yana da matafi, tsohon karamin rauta mafi yawan aiki yana da matafi. Amma idan tsohon karamin rauta mai girma yana da kashi (noise), tsohon karamin rauta mafi yawan aiki zai yi karfin lafiya a kan kashi. Wannan bai zama abin da ba ni da shi. Saboda haka, CMOS Schmitt trigger yana amfani a cikin wannan.

Waveform of Simple Signal Inverter Circuit

A cikin tsohon karamin rauta ta farko, tsohon karamin rauta mai girma bai da noise. Saboda haka, tsohon karamin rauta mafi yawan aiki yana daidai. Amma a cikin tsohon karamin rauta ta biyu, tsohon karamin rauta mai girma yana da noise. Tsohon karamin rauta mafi yawan aiki tana da karfin lafiya a kan noise. Don in karkashin wannan halin, CMOS Schmitt trigger yana amfani a cikin wannan.

Tsohon aiki na tara a nan yana nuna ci gaban CMOS Schmitt trigger. CMOS Schmitt Trigger yana da 6 transistors, kamar PMOS da NMOS transistors.

Kadan, ana bukata a sani, wani ne PMOS da NMOS transistor? Alamun PMOS da NMOS transistors suna cikin tsohon aiki ta na biyu.

NMOS transistor yana gina idan VG yana da yawa da VS ko VD. Amma PMOS transistor yana gina idan VG yana da ƙarfin da VS ko VD. A cikin CMOS Schmitt trigger, wata PMOS da wata NMOS transistors suka zama da a dutsin aiki na iya gina tsohon karamin rauta mafi yawan aiki.

A nan da kowane, zai aiki na yin da shi. A cikin hakan, PN transistor ya zama ON da NN transistor ya zama OFF. Wanda ya bari hanyar zuwa ground don node-A. Saboda haka, maida na CMOS Schmitt trigger zai zama zero.

A tare da kowane, zai aiki na yin da shi. A cikin hakan, NN transistor ya zama ON da PN transistor ya zama OFF. Yana bari hanyar zuwa voltage VDD (High) don node-B. Saboda haka, maida na CMOS Schmitt trigger zai zama high.

Tsarin Schmitt Trigger

Tsunan Schmitt trigger sun hada:

An amfani da Schmitt trigger don iya gina sine wave da triangular wave zuwa square waves.
Amfani da Schmitt triggers shine muhimmanci wajen cire noise a cikin circuit digital.
An amfani da ita don function generator.
An amfani da ita don oscillator.
An amfani da Schmitt triggers da RC circuit don switch debouncing.

Source: Electrical4u.

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Ba da kyau kuma kara mai rubutu!

Makarantarƙi:

Kawarwari Yawan Kukuna

Tushen Schmitt

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