Answer Posted / dlhylton

An op amp has high input impedance to prevent loading. When
the impedance is very high, the current that the op amp
draws is very low.

Op amps also have high input impedance because it's a
voltage gain device. In order for the op amp to amplify the
voltage, the voltage signal must drop fully across. And for
this to happen, the op amp must have high input impedance,
v=ir. The greater the impedance, the greater the voltage
drop.

Check out:
http://www.learningaboutelectronics.com/Articles/Why-does-
an-op-amp-need-a-high-input-impedance-and-a-low-output-
impedance

for full explanation

sir, please send HPCL INFORMATION SYSTEMS OFFICER SYLLABUS WITH PREVIOUS QUESTION PAPERS

4062

---

what are the advantages and disadvantages of embedded compare to vlsi,dsp?

2081

---

What are the important ic technologies used?

1088

---

Name the breakdown mechanism in a lightly doped p-n junction under reverse biased condition.

1290

---

Why does all cellular networks have same shape of sim?

1064

---

The linearity error for a digital input is indicated by what???

2156

---

Compare and Contrast- Diffusion and Drift Mechanisms

1383

---

can u split the Point code switch(PC)

2270

---

Explain what is a state table?

1133

---

Is M-ary PSK bandwidth efficient or power efficient

2094

---

what are software interrupts present in 8051 Microcontroller? Only Software interrupts//////

2824

---

plz send jto previous papers

2025

---

Can a gas be used for conducting current?

1078

---

What is the frequency range of satellite communication?

1108

---

Types of (Open Shortest Path First) Link State Advertisements (LSAs)?

2153

---