Non Inverting Amplifier - Op-Amp Designs

The input impedance of this module is very high, if U1 is OP07 it is in mega/giga ohms, use CA3140 or LF356 fet input opamps to get 1 tera ohm input impedance, but for high gains OP07 is better as it is ultra low offset. This is a good amplifier for sensor outputs, as it is a DC Circuit.

Non Inverting Amplifier - Op-Amp Designs

The zener diodes protect the opamp inputs, R1 limits current during high voltage inputs and R1 and C1 form a filter to remove some ac components, C1 should be a plastic type as ceramic and electrolytic caps are leaky. A large C1 will slow the response time, the sum of Ri + Rf should be greater than 5k so that output is not loaded. Do not connect output to voltages more than vcc/vdd, it will blow Opamp.

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Inverting Amplifier - Op-Amp Designs

This is an Op-Amp Tutorial. Here you see an Operational Amplifier in the Inverting Amp configuration. I have used OP07 as it is almost like an ideal Opamp. The ultra low offset is the best part. Then not really, CA3140 has a Tera Ohm Input resistance but offset not the best. ICL7650 approaches an Ideal Op-Amp and chopper stabilized. These parameters are good for DC Amps. Sensors, Strain Gauge Bridges Signal Conditioning need them. Then when you want a better AC performance, you can use a LF353 with a nice slew rate. Here the DC merits are not of much use.

Inverting Amplifier - Op-Amp Designs

Input Impedance of this module is Ri as pin 2 is at virtual ground, the opamp with feedback tries to maintain pin 2 and 3 at same potential pin 3 is at 0V hence pin 2 is at virtual ground. Clamping diodes protect OpAmp, Rf + Ri is between 5kE and 1ME as an opamp may be able to drive around say 5mA max

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Buffer Unity Gain Amp - Op-Amp Designs

If output impedance of a point is a high value then connecting another circuit at that point will load it, resulting in malfunction or error. Buffers are used as interface between circuits. Low impedance of an output means it can source/sink lot of current, when you need 2 opamps use LF353 or TL072 which are dual opamps.

Buffer Unity Gain Amp - Op-Amp Designs

A non-inv FET input is the best buffer, for inverting buffer use high R values. Using very high R values like 2.2M or higher requires a glass epoxy PCB and guard rings around pin 2, 3 to prevent leakage currents on the PCB reaching the PINs. Also moisture and dust has to be prevented by using RTV coating or Varnish. Use 78L05 and 79L05 for the dual supply required by this circuit

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