Logarithmic Amplifier AD8307 circuit

The circuit's input operational amplifier triggers the timer, setting its flip-flop and cutting off its discharge transistor so that capacitor C can charge. When the capacitor voltage reaches the timer's control voltage (0.3Vcc), the flip-flop resets, and the transistor conducts,...

op amp Why the resistor in this op-amp circuit

Here is a circuit diagram for a signal response test circuit from the specification sheet for a HA-5195 operational amplifier. It appears to be a non-inverting amplifier circuit with a gain of 5, along with a 200-ohm resistor connecting Vout...

Op-Amp Colpitts Oscillator

A Colpitts oscillator can be implemented using an operational amplifier, provided that the op-amp has an appropriate bandwidth. An example of such a circuit can utilize the LT1190 or LT1191. The Colpitts oscillator is a type of electronic oscillator that generates...

3 Band Graphic Equalizer

This simple equalizer circuit utilizes a single operational amplifier (op-amp) to provide three distinct frequency ranges: low frequency, mid frequency, and high frequency. With the specified component values, the circuit is capable of delivering an approximate gain of +/-20dB at...

Filtered-sample-and-hold

It is often necessary to filter a signal prior to sampling. This can be achieved using a single device. Any of the inverting or non-inverting filters that can be constructed with operational amplifiers (op-amps) may be utilized. However, it is...

op amp Basic Frequency Control Circuit

R4 prevents the output voltage from drifting toward one of the supply rails of the operational amplifier. It is understood that R4 should have a high resistance, although the reason for this is unclear. The schematic appears to be from...

Polarity Gain Adjustment Circuit

By adjusting one potentiometer, the output of this circuit can be varied from a positive version of the input signal, smoothly transitioning through zero output, and then to a negative version of the input. For instance, if the input signal...

AD Design

The right leg driver circuit is where many amplifier board circuits' common signals are summed and inverted through the Right Leg Driver circuit and sent back to the body to cancel out common voltages. This ground point could be an...

Safe-opamp-circuit

In intrinsically safe applications, it is sometimes necessary to separate sections of circuitry using resistors that limit current under fault conditions. The circuit presented offers an accurate analog output with effectively zero output impedance, despite the presence of resistors in...