# Operational Amplifier

Types of Operational Amplifier

1. Inverting Amplifier:

Fig. : Inverting amplifier

Voltage Gain,

1. Non-Inverting Amplifier

Voltage gain,

Fig. : A non-inverting amplifier

1. Voltage Follower
: - for voltage follower

Fig. : Voltage follower

1. Summing Amplifier

If R1 = R2 = R3 = R,
Then output voltage is given as :

Fig. : Summing amplifier

1. Differential Amplifier :
V0 =

Put R1 = R3 & R4 = R2
Vout =

Fig. : Differential amplifier

1. Integrator: As its name implies, the Op-amp Integrator is an operational amplifier circuit that performs the mathematical operation of Integration.
Ideal voltage output for the OP-amp Integrator as:

Fig. : Integrator

1. Differentiator Amplifier: The differentiator amplifier circuit performs the mathematical operation of Differentiation.

Vo = â€“Rf C

Fig. : Differentiator amplifier

IC-555 TIMER

Fig. : 8-PIN DIP 555 timer

# IC-555 Timer as Astable Multivibrator

The time during which the capacitor charges from 1/3 Vcc to 2/3 Vcc is equal to the time the output is high and given by

tc = 0.693 (R1 + R2) C1

Similarly the time during which the capacitor discharges from 2/3Vcc to 1/3Vcc is equal to the time the output is low and is given by
td = 0.693 R2 C1

Hence the total period of the output waveform is
T = tc + td = 0.693 (R1 + 2 R2) C1

Fig. : IC timer 555 in astable mode

Duty cycle.
The duty-cycle is the ratio of time in the high state to the total period, T and is given by

Frequency of oscillation.
Frequency of oscillation is given by

Fig. : Voltage across capacitor C1 and output voltage waveforms

# IC-555 Timer as Monostable Multivibrator

The time during which output at pin 3 is high is given by tc = 1.11 R1 C1 second

where C is in farad and R is in ohm. The equation clearly shows that width of the output pulse depends on the values of R1 and C1 only

Fig. : IC 555 in monostable mode

Fig. : Output waveforms