In intrinsically safe applications, it is sometimes necessary to separate sections of circuitry by resistors which limit current under fault conditions. The circuit shown provides an accurate analogue output with effectively zero output impedance, despite having resistors in series with the output. which is independent of RA and RB. ..
The circuit works with two 741 opamps and provides better than 20 dB gain in each channel. A better type op-amp will give a better noise figure and bandwidth. ..
This simple and inexpensive circuit can produce a dual (positive and negative) voltage from a single supply input. It is therefore extremely useful for powering opamp and other circuits that require a dual voltage from a single battery. The circuit will operate at an input voltage from around 5V to 20V and produce a output from +-2.5V to +-10V...
The amplifier drives a pair of loudspeakers using two LM3876 integrated power amp ICs (50 watts per channel), or a pair of headphones via a Meier crossfeed filter and an OPA2134 dual opamp. It provides four switchable line level inputs, and an unbuffered line level output for recording purposes. The design uses readily available good quality components, and is based around four separate PCBs; one for each power amp channel, one for the power supply board, and one for the.....
This is an opamp version of the synchronous modulator I submitted earlier. It has more consistent performance over varying power supply voltage than the discrete version, but it still has the 0.7 Vp-p limitation on the maximum input voltage...
The circuit of the unit is fairly simple, but is a bit irksome to set up. The reason is that obtaining matched FETs is not easy, so I had to make sure that the circuit would work with off-the-shelf FETs. The phase shifter is a standard opamp circuit, and has been used for this sort of application many times. After experimenting with alternative variable resistors, I decided that the FET was still the best choice, although they are fairly critical to set up, and have.....
In a lot of cars, the car-radios use amplifiers that their output power does not exceed the 5W with enough distortion in the limits of power. The problem is untied with the utilisation of external amplifiers, that will have the possibility giving much bigger power, with much smaller distortion. With given the voltage operation of car that is + 12V, we do not have the possibility of taking power above a limit. The solution is we use two amplifiers in bridge connection,.....
Opamps are very useful. But one of their major drawbacks is the requirement of a dual supply. This seriously limits their applications in fields where a dual supply is not affordable or not practicable. This circuit solves the problem to a certain extent. It provides a negative voltage from a single positive supply. This negative voltage together with the positive supply can be used to power the opamps and other circuits requiring a dual supply. The circuits operation.....
The controller uses one or more ordinary silicon diodes as a sensor, and uses a cheap opamp as the amplifier. I designed this circuit to use 12V computer fans, as these are now very easy to get cheaply. These fans typically draw about 200mA when running, so a small power transistor will be fine as the switch. I used a BD140 (1A, 6.5W), but almost anything you have to hand will work just as well...
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A opamp. medium power, here its used as amplifier of headphones with possibility drive low loads. It contains in a nutshell two amplifiers. The voltage gain, has been determined in 40dB, from the R3-4 and R11-12, for each channel, respectively. The restriction of bandwidth for each unit is regulated by the combination of R12, C2 and R13, C15, in 22KHZ. The R5, R10 attend to the adaptation of impedance earphones...
Sawtooth wave generators using opamp are very common. But the disadvantage is that it requires a bipolar power supply. A sawtooth wave generator can be built using a simple 555 timer IC and a transistor as shown in the circuit diagram. The working of the circuit can be explained as follows: The part of the circuit consisting of the capacitor C, transistor,zener diode and the resistors form a constant current source to charge the capacitor. Initially assume the capacitor is.....
This power supply circuit is highly stabilized that its output voltage will drop only 0.005% even though the load changes from 0 to 100%. Another excellent capability is that the output voltage will change only by 0.01% if the input voltage fluctuates. The capability if the circuit to be adjusted from 0.1V up to 50V is due to the application of opamp IC CA3130 in the circuit. Transistor T4 raises the output voltage to higher level, and at the same time it separates the.....
The output cable from my 20 MHz function/sweep generator dangled over the side of the workbench, the alligator clip hovering over the floor. Deeply engrossed in a project, I moved the power strip on the floor a little closer so I could plug in the circuit upon which I was working. That's when the alligator clip contacted the 240 VAC. The function/sweep generator had been gravely injured. Poking around with a scope probe, the signal output was down in the noise, but it was.....
"Class A" refers to configuring an amplifier so that its output devices remain turned on all the time. This reduces thermal variation and eliminates crossover distortion, which makes the chip perform better. To bias an op-amp into class A, you simply put a current source from the op-amp`s output to one of the power rails. Everything else is details. This article is about those details...
This circuit ensures that a blinking slowly, ie the lamp is brighter lights until a maximum is reached and then gradually decrease in strength until the lamp is off. IC1a opamp is used here to a triangular voltage generation. The opamp acts as a comparator, ie the output is at full power. If the positive input is higher than the minus input, the output of the opamp high and low otherwise. The resistor divider R1/R2 ensures that half the supply voltage to the positive input.....
This unique circuit makes your dome light look cool. Usually when the car door is closed, the dome light just goes OFF. With this circuit, you can have our dome light fade slowly in brightness and finally go OFF. This slow dimming of the light gives a very good feeling at night. It looks very romantic! The circuit can be explained as follows: When the car door is open, the push to off switch of the door is ON and hence it charges the 22uF capacitor fully. The opamp is.....
While doing research for the article Designing an Opamp Headphone Amplifier, I built a portable headphone amplifier for testing purposes. Each channel uses a single Burr-Brown OPA134 opamp in a non-inverting configuration. It has adequate current capability to drive most headphones without an output stage. I have used it with Sennheiser 465s (94dB SPL) and achieved ear-splitting volume. The amplifier is ideal as a booster for power-conserving stereo sources such as.....
This circuit produces an extremely low distortion sine wave, in spite of the non- linear devices used for amplitude limiting (D1 and D2). The reason is first that distortion (harmonics) is fed to the minus input of the opamp with far less loss than to the plus input, severely attenuating them...
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