Dear forum members ,
I am using 10 A DC current sensor for measuring the current output of a device.The actual output of the dc sensor is 2.600 V for 1 Ampere and 2.700 V for 2 Ampere and output voltage of the sensor increases proportionally withe respect increase in the current drawn by the load.There is a voltage drop of 200 mv when it is measured using the k8047 data logger.The drop of 200 mv Dc is very big for my project.I dont know the reason for the drop in voltage.Can any one clarify please.Is it due to impedance mismatch?If so wt is the solution?
The input resistance of the K8047 is fairly high: 1 Meg Ohms … Normally the output resistance of your probe should be much lower.
I have increased the gain of the dc current sensor output using an operation amplifier circuit and connected to the K8047 logger for measurement and recording.However i am experiencing voltage drop in the range of 200 mv DC.Can any one reveal me what to do to sort out the voltage drop problem
Can you draw us a schematic of what you’ve put together there? It is very hard to believe that the input impedance of an OP-AMP is affecting the output voltage of your sensor that much.
Especially of interest would be from where does the OP-AMP get its supply voltage.
Dear sir
Thanks for your reply.My problem is the out put of a DC current sensor is fed to an inverting op-amp constructed using LF351 for increasing the gain. The output of the DC current sensor is steady.But the amplified output is not steady and fluctuating when connected to a channel of k8047 data logger .The amplified voltage has been acquired and recorded using k8047 is not steady and varying .I dont know how to draw the circuit here .I can send the circuit drawn in MULTISIM if you send me your email ID.Please help me .I am using separate power supply for +12V,-12 V and +5 v for powering the op amp circuit.
cordially yours
paldurai kasi rajan