IC741 데이터 시트보기 (PDF) - Unspecified

부품명

상세내역

제조사

IC741

Operational Amplifier

Unspecified 

3 Procedure

3.1 Input bias current measurement

1. Switch off the offset-null potentiometer.

2. Hook up the circuit shown in Fig. 3(a), by choosing R1 to be 1M and connecting the loose

end of R1 (1) to the middle of the potential divider in the output (8).

3. Switch on the power supply and wait for two mins for the output to stabilize.

4.

Measure

the

output

voltage,

and

calculate

Ib1

as

Ib1

=

Vout

13.82

µA

5. Next, hook up the circtuit in Fig. 3(b) by choosing R2 to be 1M, and connecting the inverting

input to the middle of the potential divider (8).

6.

Measure

the

output

voltage,

and

calculate

Ib2

as

Ib2

=

Vout

13.82

µA

7. Calculate the input bias current as Ib = (Ib1 + Ib2)/2

3.2 Input offset current measurement

1. Switch off the offset-null potentiometer.

2. Set R1 = 1M and R2 = 1M

3. Connect the loose end of R1 (1) to the middle of the potential divider in the output (8).

Connect the loose end of R2 (2) to ground.

4. Switch on the power supply, wait for two mins and then measure the output voltage Vout.

5.

Calculate

the

input

offset

current

as

I0

=

Vout

13.82

µA.

6. Compare this value of I0 with that calculated from the input bias currents, measured earlier:

I0 = Ib1 − Ib2.

3.3 Inverting and non-inverting gain measurement

1. Set up the “inverting” configuration in Fig. 2, with R1 = 1K and Rf = 10K (keep the

offset-null switch off).

2. Zero input voltage should give zero output voltage. To check this, connect the free end of R1

to ground and measure the output voltage Vout. The voltage won’t be zero. To remedy this

problem, we have to use the offset-null fascility provided in IC 741. For this, switch on the

offset-null switch and adjust the potentiometer so that Vout is zero. Do no disturb the setting

of the potentiometer in the rest of the experiment.

6

Share Link: