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98 Threads found on Sensor Opamp
Hi. I am using IL300 optocoupler for my voltage isolation (except 1 output voltage value rest all linear to the input). I want to use the same for current sensing and connect it to my ADC. I am not sure if for the current sensing its the same circuit as mentioned in the datasheet under typica
I have a few questions regarding High pass and low pass filters when calculating a pulse rate. Why is it that in this link, The cutoff frequency is set to 0.5Hz? Why did the capacitor and resistor be chosen for the HPF? Also why does the gain and cutoff frequency have to be 48 and
Hello every one, I am working for a project , in which i should develop a sensor interface circuit to find impedance when using a TDC. Impedance range is upto 1Mohm . Input frequency is upto 1 Mhz. for find the impedance , Phase information and Amplitude should be extracted when the excited with a sinusoidal signal (till 1MHz). Phase infor
Hi, It is a MUX. 0: measure excitation current across 100R 1: measure sensor output signal 2: zero. (I assume for offset adjust) 3: unused. Klaus
The input resistance of your inverting amplifier is 1k ohms which attenuates half of the input voltage from your 1k ohms sensor that needs a load of at least 100k ohms. That is why you were told to add a buffer between the sensor and the inverting opamp circuit because the buffer can have an input resistance of 100k ohms or more.
1. I can suggest you to use an opamp with very low input offset voltage (also known as Chopper or auto zero or zero drift. the name varies with manufacturer but the functions are same). Non of the opamp which is embedded into the microcontroller will suitable to interface your sensor (except Cypress PSoC controller wich is very much (...)
my load cell sensor outputs 0-10v, but my dspic controller accepts only 0-3.3v adc signal only, how can i convert using opamp kindly help. thank you
Hello Everyone, I need to design an Operational Amplifier as an Instrumentation Amplifier for a sensor and the output of the sensor is 0.1 to 0.5 Volt. The Technology is 180nm with 1.8 volt as Vdd. Please help me in writing the specifications for the opamp and opamp architecture i should choose. Thanks in advance.
How to design an opamp Circuit for pH sensor which will be interfaced to PIC. The PH sensor gives 420 mV for 7pH and -420 mV for 14 pH. I need to design an opamp Circuit using 741 or LM358. How can I design the opamp Circuit. Further the output of the amplifier will be input to ADC of PIC for measuring the pH.
The input resistance of an opamp is important if you use a very high impedance piezo vibration sensor that has its low frequency spec's with loads of 5M, 10M and 1G ohms. At the very low frequencies of vibrations then the resistance is the same as the impedance.
Hi all, I have a low to medium level of understanding electronics. Playing with LTSpice is fun but not enough for me to make steep learning progress. Here is the problem, I ask you to help me with: A sensor with an output swinging between +3 und -3 V should be connectet to an ADC. The ADCs reading range ist 0 to +5 V. I am only interes
Can I use the famous IC741 opamp? The one labeled V- , is that V+? What would be a the best value for Vref? I presume, the bias voltage polarity is meaned as shown in the schematic. It has been BTW copied from a competitor's application note :grin: The voltage level is specified w
Not quite sure what you're trying to do there, but it looks like there's a lot wrong. 1) You've got a diode in series with sensor output which will allow only negative signals through, but your opamp is referenced to ground. I think you want to turn that diode around and maybe put a resistor to ground on the opamp input. 2) Your (...)
Use a thermistor (PTC) as temperature sensor and an opamp as comparator (with a potentiometer on the non-inverting input as reference voltage). Once temperature exceeds a value set with the potentiometer, the opamp's output will go low and can switch off a relay that is connected to your lamp. Simple circuit, $2 worth of components.
The impedance of the sensor is the "resistor" in series with the opamp's +input. The sensor should use the reference voltage for its common. Then the reference voltage should have a capacitor filter to ground. The positive feedback capacitor speeds-up the opamp's switching times.
Hello Guys, Firstly, I am new here, so please be forgiving to me :) I am trying to design a comparator for CMOS image sensor ADC. Below you can see schematic of the testbench and waveform with results. Architecture of comparator, it is standard 2-stage opamp with high gain, without hysteresis. Operation of this circuitry should be like this:
I connect LDR and PIR sensor to input of Transistor And Gate circuit and connect 4 LED 12V 1W to output . But LED is alway bright. when have no input from both sensor LED is little bright. So, I pull out input from LDR. when somebody pass PIR sensor it's more bright . And If have input from both sensor it's most bright. I (...)
Hi, I would like to design analog circuit that will detect signal from pH electrode senor and sent it to micro controller. I need analog circuit which process sensor electrode signal into ADC, from ADC to micro controller. I am thinking about Instrumentation amplifier to get low voltage dc signal from sensor electrodes. I am confusing wit
I am using ACS712 hall effect current sensor. It gives 66mV/A. I am using ADC0808 to read the value of AC current passing through real load. Now the problem is that ADC0808 reads the analog values but i need the peak value of current. How can I read this signal with
Your analog meter measures CURRENT; your ADC measures VOLTAGE. So, it would seem that the simple approach is to hook everything back up the way it is in the top picture, and measure the voltage at the junction of the meter and the sensor. Get rid of that 3K resistor on the opamp input.
Greetings, Need to know where to look to find information on how to rescale sensor voltage. I have a sensor that outputs 1.4V (rms) for 230V (rms) What kind of ways are there to change this output to 0-3.5V so I can feed it to ADC of dsPIC? Somebody told me a opamp? but I couldn't seem to figure out how to make
For the leads, I would tend to want to use shielded twisted pair for each lead. That would make them much worse antennas (a good thing). The shield (i.e. the "drain wire") would then be connected to chassis ground, near the input to the box, and connected to nothing on the sensor end. And the two internal wires in the twisted pair would be sign
Op-Amps Part 1: Scaling sensor Voltages regards, Peter :wink:
Hi, I have some basic questions regarding LDO and opamp based amplifiers: 1. When is a LDO used and why can't an opamp based amplifier be used? For e.g. I came across a sensor analog front end system. A bandgap was designed to generate a reference voltage of ~1.2V. But the ADC needed a 2.4V reference so a LDO was designed with the (...)
Hi, I was making a an op amp based circuit and came across a problem. I hope someone can help me. The circuit consists of a transducer (Hall sensor) with the output connected to an op amp buffer. This is followed by a RC high pass filter (~20Hz ) Low pass filter (~1KHz) to remove the DC bias and noise respectively. Next there is a non inve
All you need is a substance called pressure sensor and an opamp. Try an opamp non invertor. Make amplification some 10 time or 100.
Hi, Did you look at this scheme? 1. This guy is using LM358 opamp along with a LM385 reference IC, to read from PT100 sensor. You also could use this scheme. 2. Another scheme that uses ADS1247: Regard
thanks for your answer! I now understand 2. But I don't really understand 1. Cannot the window comparator itself be considered as a kind of hysterisis where the "dead window" is the hysteris? It cannot be that the positive and negative response (output signal) of the sensor is unbalanced somehow and therefore requires dif
... when the input is 3.92 V, its output is 3.98 60mV deviation is really a lot for an opamp with an input offset voltage of typ. 2mV (max. 7mV). So I think its due to the input bias current (45 nA typ., 250nA max.) times the output resistance of your sensor (which isn't given in its data sheet, but perhaps is of
Amplifying feeble AC voltage from small coil which is having the presence of bar magnet, which i want to use as a sensor of movement someone help me in making in amplifier, can i build with opamp ?
Somebody please help me interfacing PT100 sensor with ADC port. I need to interface PT100 with an ADC Port, PLease help me with the opamp circuit.
1. Connect resistor between sensor resistor (200 Om) and opamp input . 2. Input Op Amp must be pulled to Vcc and GND through Fast/Schottky diodes (in reverse bias). It restricts input voltage level on the range -0.7V and VCC+0.7V
Been working lately on opamp's cause of a PIR sensor, and learned that a voltage follower/unity gain stage is a good circuit if u want somehow connect diferente impendance circuits. But i think that the 20k load resistor sugested before is a good starting point. Nothing better than the usual trial/error headaches.
It's readliy available and cheap as hell. The lm324 and lm358 are probably the most common op-amps you can get , oh and maybe the 741 , still :0) Using LM324s in PIR detector applications has almost nothing to do with their gain-bandwidth of 1 MHz. LM324 is a low-cost quad opamp that can be used with single-pola
Hi I am sensing ac voltage using opamp(MCP6024) in differential amplifier configuration.When i connect the CRO probes at the output lot of noise is observed in the output. I put 1Kpf ceramic capacitor across the output and ground , however there is no effect.How do we avoid sensor noise pickup.I have attached the waveforms of the actual waveform (
You can use a resistor divider, or you can make a simple attenuation stage using an opamp. Either will work, since I'm assuming that your sensor output voltage is a slowly fluctuating DC voltage. Depending on the output current that your sensor can deliver, a resistor divider may be appropriate, though it will probably be slightly less (...)
hi. i want to know the circuit diagram for the piezoelectric pressure transducer that converts a mechanical force upon the sensor to electrical signal . please suggest some circuit using opamp.
The sensor to be used is pH probe, it gives rise to potential difference when dipped in solution. The potential difference is in mV range, this can be amplified using an opamp to make it convenient to be used with ADC and microcontrollers. You can set certain limit say 0.1 change (pH changes from 7 to 6.9), this will cause certain pin of an output
This is allmost same circuit...... Light or Dark sensor Circuit LM741 Light Dark sensor Circuit - Electronics -for reversed action exchange LDR & R1 In this circuit reaction time to adjusted light level is quite short 2..3sec. need modification, so that switch reaction del
Weight sensor --> opamp derivator --> schmitt-trigger --> logic/microcontroller
I would use the temperature sensor output, programable LDO or voltage reference and comparator (or opamp) You can then set different switching voltages defined by LDO for the comparator. Some logic around would be needed also.
I presume, that you are talking about noise, not 50 Hz hum caused by a inappropriate measurement setup. the opamp being wired as voltage follwer has a rather high i/p impedance and that's causing a relatively large noise signal. The noise is generated by the sensor itself rather than the buffer impedance. The latter adds current
"Raising" the sensor ground is only suitable, if no error currents or interferences are injected by the connected circuit. If the sensor is e.g. connected through long cables, it won't do it. Regarding OP offset voltage, you also have the option to cancel it in your software. You should consider, that the zero uncertainty caused by regular resis
Normal class A amplifiers have noise levels higher than few microvolts and your sensor voltages will get badly engulfed in that . It is advisable to use a differential mode amplifier with a capability to curtail threshold noise . The same is an easy build using an opamp like OP7 or LM10 ..
I would expect a gauge sensor rather than a MPX5700ASX absolute pressure sensor for this application. But the pressure is most likely sufficient to ignore the atmopsheric pressure sensitivity of the absolute type. Nevertheless it introduces an additional output offset of about 0.65 V in addition to the built-in zero offset. I guess, your circuit
Hello, I have an input signal(0.5v to 1.5v) from a sensor and I want offset this to 0v- 10v using an opamp. Vin min = 0.5v ; Vin max = 1.5v : Vout min = 0v : Vout max = 10v Pls how will I do this? I got an equation on the web which states that my gain equals : G = (Vout max - Vout min)/(Vin max - Vin min) and my offset voltage wi
Dear ALL, My question is centered on ADC's of microprocessors connected to sensors via ADC's. When do we need an opamp? and Why do we need it, is it a buffer? let's say I have a PIC or 8051 microcontroller ADC connected to a sensor that needs opamp, what opamps are suitable? Best Regards, Basel
dear friends, can i take the data from the inbuilt float sensor in a vehicle for my vehicle tracking system.please reply thanks in advance.
i have an application where i need to simulate the output of a sensor which has an output impedance of 50 ohms, 0.45-4.5v is the range of output voltage for various pressure do i design a simulate a circuit to simulate this so that i can give the resulting signal to an ADC? An ideal source with a series 5
HI Guys, i have a problem on this circuit.. it is a fire alarm circuit with a heat sensor lm35... i want to connect a relay in to it, so that if a heat is detected the relay will be trigger is it possible.... please i really need your big help..