Operational Amplifiers : 
With a few Op-Amps and a regulated Power supply,
many Instrumentation and Process control equipment can be
designed. The Human Brain understands Numbers, Quantity and it
regulation very well ! On the right you can see a analog controller
based on opamps and
discrete devices. A Heater, Fan and Motor is regulated, controlled and
timed for a process.
Analog is about numbers, the circuits can be understood and designed
mathematically or empirically. Designing and
Building a True
RMS Rectifier with Op-Amps, will help a
designer digest many Op-Amp capabilities.
Read this to learn to use Op-Amps -
Basic
Semiconductor Circuits Manual
Things you ought to know about Op-Amps -
OpAmp part numbers from various semiconductor companies are designed
for both General purpose and special applications. Some have
to be
cost-effective for consumer low-cost equipment, while others may be
advanced in specs, closing in on an ideal Op-Amp.
Instrumentation
opamps are used
for accurate and low drift applications. These Op-Amps have stringent
specifications and are used in the fields like Aerospace or Medical
Electronics. A pre-amplifier for an FM Radio may
need to be low-priced. Test Measurement needs Op-Amps which have near
ideal specs in the area of measurement or application. CMOS low-power
devices are used when designs are made for portable gadgets.
- Outputs cannot be Loaded beyond the drive
capacities, Note Resistors and Output Load.
- Inputs draw a small bias current and will load
the
signal sources, compensate design.
- Op-Ams AF-RF or Switching performance study
with Slew rate and Bandwidth.
- Power consumption of some Op-Amps are more and
some very less, choose wisely.
- Look for Standard Pin-Outs, Price, Popularity
and study Abs. Max, AC and DC Specs.
- Use Packages with multiple Op-Amps like LM324
to save board space
and assembly time.
- Op-Amps and its 1% MFR resistors should have a
separate supply and far from hot parts.
- Ultra Low Offset Voltage is required, when you
wish to amplify a DC level of say 500uV.
- Guard rings to be used for High impedance
inputs and EMI-RFI Shielding for AF Amplifiers.
- Glass epoxy PCB, clean surface, Pins and Tracks
protected from Moisture and Chemicals.
- Avoid Ground Loops, Have regulated Low ripple
Power supplies. Dynamic Isolation.
09:07 25-Oct-08
Anantha Narayan
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