runandrew

Hello I have a homework problem that involves solving for the voltage gain in an op-amp circuit with both positive and negative feedback. I need to find the relationship between in input voltages V_s1 and V_s2, and the node just before R_L, which I will refer to as V_o. I have never dealt with positive feedback before. But, I plan on using super-position to solve the problem. So, the final relationship will look like V_o = k_1*V_s1 + k_2*V_s2, where k_1 and k_2 are some gain constants. By, turning V_s1 off, I get an inverting amplifier, so V_o' = (-R_4/R_2)*V_s2. Is this right? And then, by turning V_s2 off, I get a positive feedback circuit, but I am not really sure how to solve it. Could someone help me out? Thanks.

In respect to cost, a torque sensor can be very expensive. I am looking for a low-cost solution. Enthalpy - can you expand on the known weaknesses of my design? Also, to solve for T_1 by summing the moments about the hinge point (taking counter clock-wise as positive) --- -T_1 - T_2 - W*(L/2) + F_y*L = 0 (T_2 = 0, no external torque input) So, T_1 = F_y*L - W*(L/2) --- Is this correct?

I'm creating a test setup similar to a dyno and am trying to detect the torque from a motor shaft. I am using an Eddy Current (EC) Brake to absorb the torque coupled from an engine. Below is a rough sketch of the test setup. The brake will be centered on a plate that is allowed to rotate on one side and is supported by a load cell on the other. Can you guys help me with the statics of finding T_1 (Torque from the motor) knowing the values of W, L and F_y. Thanks!

Hello, I am looking if there is a material that has variable thermal resistance as its temperature changes. Please refer to the image below. I am trying to find a material that as heat is added to the outer surface, the inside surface can only reach a desired temperature. So in a sense, the material regulates the temperature at T1. For example: if the outside surface temperature, T2, was at 80C then inside surface temperature, T1, would be held at 60C at steady state. Thanks, Andrew