Op-Amp Circuits


Harmonic Generator With Single Opamp

Quartz crystals have the property that their amplitude/phase characteristic repeats itself at frequencies that are an uneven multiple of the fundamental frequency. There are so-called overtone crystals that are cut in such a manner that they possess this property to a greater extent. However, in principle, any crystal may be used on one or more […]


an Op Amp with Discrete Components

You can use three discrete transistors to build an operational amplifier with an open-loop gain greater than 1 million (Figure 1). You bias the output at approximately one-half the supply voltage using the combined voltage drops across zener diode D1, the emitter-base voltage of input transistor Q1, and the 1V drop across 1-MΩ feedback resistor […]


Subwoofer Lowpass Filter using uA741 Single Op-Amp Ic

This is the simplest Sub woofer Low Pass filter Circuit using uA741 single op amp ic. The circuit is very low cost with respect to their work. The cut off frequency of this circuit is 25Hz to 80Hz maximum. Using this circuit , you can easily design a 2.1 Sub-woofer Speaker System at your own […]


Zero Gain Mod For Non-Inverting Opamp

Electronics textbooks will tell you that a non-inverting opamp normally cannot be regulated down to 0 dB gain. If zero output is needed then it is usual to employ an inverting amplifier and a buffer amp in front of it, the buffer acting as an impedance step-up device. The circuit shown here is a trick […]


Opamp With Hysteresis

At first glance, the circuit in the diagram does not look out of the ordinary, and yet, it is. This is because it combines two characteristics that are usually assumed to be incompatible: hysteresis and a high input impedance. In a standard op amp circuit, this is, indeed, true, because the creation of hysteresis is […]


Low Cost Bass-Treble Controller Using Op-Amp 741

This is simple but powerful bass, treble, volume control is made by General Op-Amp IC LM741. The input voltage is 12V, but it will also work with 9V and 6V. This has inbuilt pre-amplifier also. Left channel is shown. Right channel is same. Parts List: IC LM741 ×1 T/C 10k,22k,100k All x1 Triansistor BC148/548 = […]


Dual Opamp Buffered Power Supply

There will be instances where the currents from each supply will be unequal. Where this is the case, the resistor divider is not sufficient, and the +ve and -ve voltages will be unequal. By using a cheap opamp (such as a uA741), a DC imbalance between supplies of up to about 15mA will not cause […]


Regulator power supply with op-amp

Power supply circuit has a first amplifier using op-amp is IC uA741. Op amp circuit that is used only one, but it also features an adjustable voltage, which is steered by a trimpot resistors. Rtrim will set the input to the IC input on pin 2, so that if the detainee on Rtrim which will […]


What is the difference between op amps and comparators?

While both operational amplifiers and voltage comparators have been with us since before 1970, the similarities and differences tend to be vague. This discussion will help in understanding this important issue. I well remember the first time that I saw an operational amplifier; it was 1965 at Cambridge Electron Accelerator –it was a mysterious box […]


RS Flip-Flop Using OP-AMP

This RS flip-flop is op-amp version of classic flip-flop which uses two inverting amplifier. The non-iverting input is floating, and we can assume that the voltage level of this floating pin is between VCC and ground, while the outputs will always be high or low. The high level of the output will be 1-2 volts […]