{{fa>pencil?32}} {{drawio>pic3_3_1 }} Imagine that you work in the company "HHN Mechatronics & Robotics", which is a cheap mobile [[https://en.wikipedia.org/wiki/Electrocardiography|EKG]] – So you want to build a measuring device for the electrocardiogram or the cardiac voltage curve - for athletes and those in need. The measurement signal has only a few millivolts and microamps. In order to protect the signal from electromagnetic radiation on the way from the glued-on electrode to the evaluation electronics, a [[https://en.wikipedia.org/wiki/Electromagnetic_shielding|electromagnetic shielding]] placed around the line (see , above). However, since this creates a parasitic capacitor, a colleague suggested active shielding. The shielding is always kept at the measuring voltage that is applied to the line via a voltage follower (see , under). The parasitic capacitor is never charged due to this structure, since the same voltage prevails on both sides - there is no falsification of the signal. **It is important for the application that the voltage follower reacts quickly**. You are supervised with the design of this voltage follower and should use the available operational amplifiers $\rm LM318$, $\rm uA741$, and $\rm uA776$ analyze in the voltage follower circuit. Write a short report (problem description, circuit in TINA TI, results, discussion) and use TINA TI for the solution. - Recreate the circuit described above for a realistic operational amplifier in Tina. Use a voltage generator as a source [[https://en.wikipedia.org/wiki/Heaviside_step_function|unit step]] with the amplitude $U_\rm A = 1.0 ~\rm V$. - Simulate over ''Analysis''>>''Transient…'' the time course for the specified operational amplifiers. \\ Determine the time that elapses until the initial value of $0.1 ~\rm V$ for the first time $0.9 ~\rm V$ achieved ($10~\rm %$ to $90 ~\rm %$ of the amplitude, too. It is called [[https://en.wikipedia.org/wiki/Rise_time|rise time]]). - Describe the passage of time in each case. Are there any other differences besides the rise time? - Based on the information provided, which of the three op amps would you choose for the problem? In-depth information (not relevant to the exercise): * Paper [[https://pdfs.semanticscholar.org/f2b9/2ee5f3e3adb034e18ddb85bd3770dc8c2c29.pdf|on the Stability of Shield-Driver Circuits]] * Detailed description of a [[https://www.elektronik-kompendium.de/public/schaerer/diffemg.htm|EMG/EKG Vorverstärkerschaltung]]