The 8 fundamental IC 741 based op amp circuits presented here are not only interesting but also very amusing to build. The included circuit ideas like inverting and non-inverting amplifiers, tone control and regulated power supply will surely intrigue you. Circuit diagrams are also attached with the article.
We all are probably aware regarding the high versatility of the IC 741. Amazingly an infinite number of 741 opamp circuit design ideas can be wired by adding just a few passive components to it. We investigate a few of them here. IC 741 is one of the most versatile and multipurpose op-amp and can be wired up in numerous different ways. Let’s study some of the important 741 opamp circuit design configurations:
1) Inverting DC Amplifier:
Sometimes it becomes important for amplifying DC voltages, the diagram above shows how the IC can be wired up into an inverting DC amplifier circuit. As the name informs a DC input to the IC will be amplified at its output but will be just the opposite with polarity. VR1 may be used for adjusting the gain of the amplifier.
2) Non-inverting DC Amplifier:
This configuration is similar to the above circuit, the only difference being the output response, which is always equal to the polarity of the fed input voltage.
3) Inverting AC Amplifier:
The figure shows how the basic inverting DC mode of the IC can be simply modified into an inverting AC amplifier design. This circuit is intended to be used with AC or oscillating input signals, primarily for amplifying minute frequencies. C1 and C2 form the input and the output coupling capacitors. Again here the gain may be varied using the pot VR1.
4) Non-Inverting AC Amplifier:
The 741 op amp circuit is similar to the above explained design; the only difference being the output of the circuit provides oscillations in phase with the input whereas the previous design produces oscillations with opposite phase to that of the input.
5) Active Tone Control:
The opamp IC741 can be very effectively used for processing audio frequencies and customizing them as per one’s own choice.
Folks who prefer more bass in music may achieve it by just adjusting the bass control shaft whereas those who appreciate extra treble with music may do the same through another similar control reserved for the purpose.
The circuit diagram shows how by adding just a few passive components with the IC 741 a neat little active tone control circuit can be built.
For the given values, the circuit provides a bass boost of 12.5 dB and a cut of 10.5 dB at around 100 Hz.
The treble chill is of 8.8 dB with a cut of 9.8 dB at around 10 kHz, with respect to the set gain of the device at 1 kHz. The circuit also features high input impedance and low output impedance.
6) Regulated Power Supply Circuit Using opamp IC 741
The final diagram of this article shows a classic regulated voltage DC power supply using 741 opamp circuit design.
A cheap zener / resistor voltage reference is used to provide a reasonably stable reference to the non-inverting input of the IC.
The pot VR 1 is used to set the output voltage right from zero to a maximum of 15 volts continuously. A Darlington pair transistor is used at the output to enhance high current delivering capacity.
However another transistor T3 has also been incorporated to check the above current if it tends to drift beyond limit.
The control limit may be set by varying the value of the resistor R6.
The next a couple of interesting application IC 741 op amp circuits using which includes a simple power amplifier circuit and a regulated power supply circuit
7) Power Amplifier Circuit using IC 741
The above circuit diagram shows how the IC 741 can be configured as a high power amplifier circuit.
Though the maximum power of this amplifier is not more than 4 watts, the amplifier provides relatively good response with the applied frequency. The distortion of less than 0.5% and has a bandwidth of over 20kHz. The amplifier requires a minimum input of around 150 mV.
8) Regulated Power Supply Circuit using IC 741
The next circuit shows the IC 741 being wired up for providing a regulated power supply with an output which can be varied as per ones own requirement.Basically the IC is configured as a comparator cum driver for the proposed power delivering purpose. The employed zener diode has been included for fixing the non inverting of the IC with a constant refernce voltage.
An additional transistor BC107 has been included for making the circuit short circuit proof and also overload protected.
The output volts can be varied by adjusting the 10 K pot while the maximum current can be set by selecting or varying the 0.6 Ohm resistor appropriately as per the needs.
Well, these are the few popular IC 741 based opamp circuit ideas that I could collect and present, if you have more ideas regarding the topic please feel free to share them through the comments...