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Adc Negative Input

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48 Threads found on edaboard.com: Adc Negative Input
Hi, If the adc will survive, and if the adc will operate correctly is written in the datasheet. Klaus
Did you bias the 1V pk-pk signal around 1.65V? Your signal is well within the +/-1.25V range of the adc input. I also suspect you are interpreting the data wrong and it is the negative side that is missing, I'm not going to check but I would imaging that the adc uses a 2's complement output. Well I checked anyway (...)
by using difference amplifier will there be any adc value loss Applying 5V reference will necessarily result in not fully utilizing the adc range with 5V rail-to-rail OPs. Using higher OP supply voltage brings up a problem of violating the adc input voltage range. Best solution is probably a slightly lower Vref, e.g. 4 or (...)
Hi, I'm not getting the right voltage What can we know fro this infirmation? * is the result negative, positive? * is it too higb or too low? * does it differ 100% or 1% or only 0.01% --> the only way is to read the adc's datasheet. It telks you all you need to know. There are so many different adcs with so many different (...)
The maximum output of 5V is made of 2^ 12 steps, so a signal of less then one step will not produce an output. If you are measuring AC, then in the absence of an input signal you have to bias the input to + 2.5 V, so the input can go positive and negative from this value. Also the adc works on the peak (...)
Do as Klaus suggests but also bear in mind that most PICs allow you to connect the positive and negative adc references to external pins. It might be possible to use the reference as a differential input and keep the actual adc input at a fixed voltage. I've never tried it but it sounds feasible. Brian.
Hello, YES ! Resolution = Vref/ N bits adc more datas ! the specsheet of adc
Your negative voltage has two wires, a negative output and a common output sometimes called "ground". If the circuits are not earthed then if you simply swap the wires then the negative wire can be the common input to the adc and the common wire can be a positive voltage input to the (...)
Hey Guys I need to be able to read voltage readings from 9V - 20V and from 70V - 140V with a Atmega 168 5V adc input. Now ive tried the simple resistor divider but because im a really cautious person, I really do not like the idea of high voltage NOT being isolated from my MCU. So ive looked at some circuits with Op-Amps. Problem with the Op
Hold the Phone.... "RF devide" you mean RC divider. this adc does not do RF..... 200 kSPS is max
Hi y'all, I have a converter that is designed to output a -100V but now I find it challenging to read that on adc. My first approach was to use an inverting amplifier with a gain of 1, the problem is that i'm not sure if the op-amp will be able to handle 100V because most of the amplifiers are rated at low voltages. Can anyone help me on this. Tha
C5/R15 will cause malfunction of the circuit. negative halfwaves are clipped by the input protection diode of the adc input. The most simple solution is to omit the highpass, send the 2.5V centered AC signal to the adc and process it in a suitable way. If you want to convert the AC current to a DC voltage (...)
Surely the voltage divider will not treat positive and negative half cycle differently. I rather guess you didn't describe your setup well and have additional components connected to the voltage divider output. If you e.g. connect it to a 0-5 V adc input, the negative half cycle will be cut because it exceeds the (...)
This Source degeneration Gm-cell with negative-impedance-compensation(NIC) technique is used to design loop-filter for 2nd order Sigma Delta adc. I dont know what are the parameters/specifications needed for the design of the adc. Also i need input parameter values like Vsin, Vref, Vss for this Source-degeneration Gm-cell. (...)
No pins of 8051 can accept analog voltages. So you need an adc converter. If it is a matter of reading the applied voltage only, then why don't you rectify the supply. This way you can rule out the negative half cycle... Use a rectifier & a good filter, convert it in dc, read through adc, multiply by 44( if step down is 220v - 5v) & divide (...)
You need to reduce input voltage and shift by 1V to avoid negative values. Shift input voltage by adding a DC source of 1V, so new range will be 0 - 4V and then add a divider with factor 2, so new range will be 0 - 2V; with these range value can go to MAX1415; in software code need to take account these operation (shift and scaling). REF+ (...)
Hello , I am doing Image acquisition using Analog devices AD9643 Digitizer and HSC EVAL C Data Capture Board. I have 71 Khz low freq input square pulse ( +5 Volts and 0 volts TTL wave ) and clock square running at 100mhz. When I get the waveform using the software I see it looks like it is not pure signal anymore , it has negative parts like
You can see this things from Pico Tech company : I think that you should use RF probe on out of audio amplifier or you can use scope x10 probe just like Pico example, before speakers, and before amplifier on input its lower voltages you can use adc with some simple adapter, to monitor positive and negative values. If you plan to make some (...)
if you mean a 5K+1K divider then the ratio is 1K/(1K+5K) =1/6 so with 12v in you'll get 2v output. Have you applied the correct calculation for the current in the input from the OPAMP? (adc*3500)/1023 gives you the input voltage in mV but you need further calculations to get the current, you need to divide this with 5 to get the voltage at (...)
One way to do it is to use an OP-amp connected as a summing amplifier and add some offset to get the output voltage for the zero point in the middle of the adc range.