70009 Parallax Inc, 70009 Datasheet - Page 107

• Manufacturer Part Number: 70009
• Description: BOOK UNDERSTANDING SIGNALS
• Manufacturer: Parallax Inc
• Type: Signal Analysisr

Specifications of 70009

• Style: Book
• Title: Understanding Signals
• Contents: Guide to Generate, View and Measure Wave Forms
• Product: Microcontroller Accessories
• Lead Free Status / RoHS Status: Not applicable / Not applicable
• Other names: 70009PAR

Chapter 8: Operational Amplifiers
many types of amplifiers, each with different characteristics. This chapter will introduce
you to simple signal conditioning with an operational amplifier, commonly called an op-
amp (Figure 8-1). Op-amps have many, many potential functions in a wide variety of
applications, but our introduction will be limited to a few common examples.
OP-AMPS AND THEIR USES AND LIMITATIONS
The op-amp is a very easy to use voltage amplifier. It accepts a voltage as an input and
produces a mathematically related voltage on its output. Resistors can be used to
configure the mathematical function that dictates the related output. By using a formula
to select the input resistor (Ri) and the feedback resistor (Rf), you can set the gain of the
op-amp. The gain is a numeric multiplier that refers to the relative difference between
the voltage of the input signal and the voltage of the output signal. Therefore, once you
know the gain of a given op-amp circuit, you can multiply the input voltage by the gain to
get the output voltage. For example, an op-amp with a gain of 2 will have an output
voltage twice the input voltage.
There are limits to the op-amp that need to be considered before proceeding. The main
limiting factors are:
Supply Voltage
Supply voltage and output range are related. An op-amp cannot create output signals any
larger than the voltage applied at the Vcc and Vee pins. This output voltage (or range) is
called the dynamic range of the op-amp. Some op-amps can have a dynamic range as
large as the span of the voltage supplied; they are called rail-to-rail op-amps. For
Amplifiers are used in everything from car stereos to medical equipment. There are
•
•
Supply voltage and output range
Slew rate
Non-inverting
Inverting
Input
Input
Vcc
Vee
Output
Figure 8-1:
Op-amp schematic
symbol