Week 3 Activity

Part 1:  Re-construct integrator circuit & connect power amplifier circuit 

This week we re-constructed our integrator circuit to get a correct output voltage waveform . The circuit diagram was the same as previous diagram. 

We used computer to calculate and get a suitable value of resistor and capacitor we use. According to the calculation result we drew a linear relationship diagram of the gain and frequency. We found that if Rc is too small, the output waveform will distort, if the capacitor is too small, the capacitance will have slightly influence on the output signal. Then we need to make Rc lagger than R, so we chose Rc=330k, R=10k ohm and C=10nF.




The problem was that when we only provide a square wave input signal to the general amplifier, the output waveform was normal and we got a waveform which was accord with expected shape. However, when we provided both square wave input signal and a DC 5V voltage to the amplifier, the input signal kept normal but output signal disappeared. We adjusted the button and found the output signal was sinked.

Then we connected the power amplifier circuit. We used two capacitors, power amplifier and current transducer.




We connected the power amplifier circuit but haven’t test it.

Part 2: Wind the coil

We used a thin, fexional, long plastic tube. Then we wind the wire around the plastic tube. The winding wire is an enameled copper wire, the type is CUL 100/0.40 FA-Nr.:719062. We made every turn of the coil close to each other tightly.

Part 3: Summary and goals for next week

This week, we finished winding the coil and building power amplifier circuit but haven’t calculated the theoretical value of the coil and test the power amplifier. The integrated circuit still existed problems in output signal. We spent much time on working out the reason and we found we didn’t connect the negative input part to the amplifier. We decided to finish it next week.

For next week, we plan too :
1. Calculate the theoretical value of the coil (eg:  turns per meter, voltage).

2. Complete building integrated circuit and get a correct output signal, then connect amplifier circuit and integrator circuit together.

3. Test power amplifier circuit and connect power amplifier and current transducer together.

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Week 1 Activities

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Part 1: Preparations before the lab After getting all of the experiemnt components, the first step we did was to check the modle type of every components and search their properties and usage in the global circuit. We set a primary image of the rogowski coil circuit by looking up online materials and the circuit we decided to use is like: We dicided to wind the coil but we did not find a suitable material to wind it. Then we dicided to build the integrator circuit first. The integrator will be used to integrate the voltage generated by the coil in the global circuit. Part 2: Build the integrator circuit The following is our disigned circuit diagram and we built the integrator circuit according to the diagram. We chose several 10k ohm resistors and a 330k ohm resistor. The capacitor we used was 10nF, 100nF. The input AC voltage was 50kHz, 3V square waveform and DC input is 5V.  This is the circuit we built. We changed the resistance, capacitance and...
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Week 5 Activity

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Part 1: Finish integrator and amplifier circuit We found that the theoretical voltage of the coil calculated last week was wrong. The radius should not be the radius of the copper wire, it should be the radius of the coils. We measured the diameter of the coil was 2.4mm, using the same calculation steps as last week and the theoretical voltage should be 3.75*10^(-6). First we finished building the integrator circuit and got the expected output waveform. We changed the circuit diagram we used before. The final circuit of integrator was: The input signal was a 120mV, 50kHz square wave and the output signal was a -1.3V, 1.667 MHz triangle wave. The output signal was amplified by about 10.83 times.    (Integrator circuit) Then we built the amplifier circuit. We designed the voltage gain of the amplifier circuit is 1000. According to: G=1+50k/Rg, we calculated Rg=505.05 ohm. However, the output signal was opposite with what we expected. The output voltage wa...
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Week 4 Activity

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Part 1: Power Amplifier Circuit First we built power amplifier circuit. According to the instruction book, we knew we need to used two 1000 μF capacitors connected with power amplifier. Then we inserted a resistor to measure the output signal. According to the instruction book of power amplifier, it requires a symmetric DC power supply with an output range of 30 to 35V. In the experiment we provided a 30V DC power supply.  After testing the power amplifier circuit, we put current transducer into the circuit but the result was incorrect. We decided to finish this part in next week. Part 2: Theoretical voltage of coil We estimated the ratio of number of turns to length 1cm. The estimated result is 21 turns per centimeter, so N/L=2100 (turns per meter). Then we measured the coil diameter by electronic digital caliper is 2.4mm so r=1.2mm. In the experiment, the signal frequency we used was 50kHz. The calculation of coil theoretical voltage is following: ...
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