application of op amp in hindi | Op-amp uses

Application of op amp in Hindi 

Op amp as an inverter (inverting amplifier):-

In inverting amplifier output signal is 180 degrees out of phase I.e inverted with respect to input signal.

Current in resistor R, I1 = Vi-V2/R

Current in resistor Rf, I2 = V2-Vo/Rf

Vo = Ad(V1-V2)

apply kcl at point A:-

Ii = I2+Ii

Ii = I2              ( Ii = 0)

fig - inverting amplifier

Vi - V2/R = V2 - Vo/Rf

V2 = V1 = (virtual short circuit) 

Vi/R = -Vo/Rf  

Vo/Vi = -Rf/R

Vo ∝ Vi                  

(-) sign indicates inverting output (180) phase shift.

Non inverting amplifier:-

I1 = 0-Vi / R

    = -Vi / R

I2 = V1-Vo / Rf

Apply kcl at point A

I1 = I2+Ii

    = -Vi/R = V1-Vo/Rf

V1 = Vi{virtual short circuit}

-Vi/R = Vi/RF - Vo/Rf 

Vo/Rf = Vi/Rf + Vi/Rf

Vo/Rf = (1+Rf/R)

• in this there is no(-) sign.
• output and input are in same phase {0 degree ps(phase shift)}.

OP-Amp as an Adder:-

Ia = Va-V2/Ra

Ib = Vb-V2/Rb

Ic = Vc-V2/Rc

I = VC2-Vo/Rf

Kcl rule से:-

fig - Adder

Ia + Ib + Ic = 1

Va-V2/Ra + V b-V2/Rb + Vc-V2/Rc = V2-Vo/Rf 

(V2 = Vi =0) virtual ground

Va-Vo/Ra + Vb-0/Rb + Vc-0/Rc = -Vo/Rf

Va/Ra + Vb/Rb + Vc/Rc = -Vo/Rf

Va/R + Vb/R + Vc/R = -Vo/Rf

When

 Ra = Rb = Rc = R then 

Va+Vb+ Vc/R = -Vo/Rf

Vo = -Rf/R (Va+Vb+Vc)

Vo ∝ (Va+Vb+Vc)

An adder circuit produces on output proportional to the some of inputs.

Subtractor:-

it is a non-inverting amplifier 

Vo'/V+ = (1 + Rf/R)

Vo' = V+ (1+Rf/R)

V+ = Vb*Rf + 0*R1/R+Rf

V+ = Vb*Rf/R+Rf

Vo' = Vb * Rf / R+Rf   * (R+Rf) / R

Vo' = Vb*Rf/1 * /R

fig - subtractor

Vo' = Vb*Rf/R

It is a inverting amplifier:-

from Vo/Vi = -Rf/R 

Vo"/Va = -Rf/R

Vo" = -VaRf/R

Vo = Vo' + Vo"

Vo = Vb*Rf/R + (- Vb*Rf/R)

Vo = Vb *Rf/R - Va*Rf/R

Vo ∝ (Vb-Va)

Differentiator (अनुकूलन ) 

The differentiator circuit produces and output proportional to the derivative of its input.

Ir = V 2-Vo/R

Q.C.V से 

charge in capacitor 

a = c(V1-V2)

".(V1=V2=0)

Q = c.vi

Ic = dq/dt 

Ic = d/dt[c.(V1-V2)]

Ic = c*d/dt (V1-V2)

point A पर kcl लगाने पर 

Ic  = Ii+Ir

Ic = 0+Ir

Ic = V2-Vo/R

cdVi/dt = -Vo/R

Vo = -Rc*dvi/dt

Vo ∝ dvi/dt

Integrator*

Ir = V1-V 2/R

Q = c.Vi

Ic = dq/dt

   = dc/dt (V 2-Vo)

Ic = -cd.Vo/dt           (kcl लगाने पर) 

Ir = Ic

Vi/R = -cd.Vo/dt

dVo = -1/Rc.Vidt        (taking integration on both side:-)

∫ dVo = - ∫ 1/Rc * Vidt

Vo ∝ ∫ Vi.dt

An integrator produs and output proportional to the integral of this input.

Schmitt Trigger :-

Schmitt trigger is a comparator with positive feedback which convert an irregular wave into rectangular wave form. 

fig - Schmitt trigger

Vi = V o.R21/R1+R2

Vut = R2/R1+R2 * (+Vsat)

Vlt = R2/R1+R2 *( -Vsat)

Vut = Upper threshold voltage

Vlt = Lower threshold voltage 

When input those higher then Vut then output those +Vsat to -Vsat when input those lower then Vlt then output those -Vsat to +Vsat

Sampling time:- 

The time during which sample and hold circuit generates the sample of output signal is called sampling time.

Holding time:- 

The time duration of the circuit during which it hold the sample values is called holding time.