Biasing LM741 for Single Supply with Split Resistor Biasing

 LM741 operational amplifier is old but a popular operational amplifier integrated circuit which is still available in electronics market. In many circuit design it is desired to operate op-amp like LM741 with single supply voltage. Here it is shown how to bias LM741 op-amp so that single supply voltage can be used. There are couple of op-amp biasing methods and here we will use the split resistor biasing method. 

The following picture shows LM741 integrated circuit(IC).

LM741 integrated circuit


In the tutorial how to bias non-inverting op-amp amplifiers, we explained the different types of op-amp biasing techniques for non-inverting amplifier which are voltage divider biasing, split resistor biasing and buffer biasing. And in the previous example tutorial how to operate LM741 with single supply we showed how to use voltage divider biasing method to bias LM741 op-amp for single supply and in the tutorial Testing Non-inverting LM358 Amplifier we showed how to use biasing technique to operate LM358 op-amp for single supply. Here we will use split resistor biasing technique to operate LM741 op-amp with single supply voltage.

The circuit diagram of LM741 non-inverting amplifier with single supply with split resistor biasing is shown below.

Biasing LM741 for Single Supply with Split Resistor Biasing

 In the circuit diagram above, a single supply voltage of +5V has been used. The capacitor C1 and C3 are the input and output coupling capacitors and capacitor C2 is the decoupling capacitor which is required in ac coupled amplifiers. How to calculate the capacitors values was explained in the tutorial how to bias non-inverting op-amp amplifiers. The resistors R3 and R4 are the split resistor biasing resistors. When these resistors have equal values then the input is biased to the mid voltage value between the power supply and ground which in this case is 2.5V. The resistors R1 and R2 provides the gain of the non-inverting amplifier. 

The circuit above assembled on a breadboard is shown below.

LM741 single supply split resistor biasing

We can test the designed LM741 non-inverting amplifier circuit with Labview PC oscilloscope or Matlab/Simulink function generator, oscilloscope and spectrum analyzer. The tutorials how to Build BJT amplifier and test with Soundcard based PC Oscilloscope and testing of self biased BJT amplifier on breadboard with PC oscilloscope explains how to use Labview PC oscilloscope and the tutorials LM324 op-amp Integrator testing with matlab simulink oscilloscope and Square wave generator using LM358 explains how to use Matlb/Simulink to test the circuit.

The following picture shows input sine wave signal and the amplified output signal using Labview oscilloscope and function generator.

The following picture shows spectrum analyzer which shows the input and output frequency.

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