This preview shows page 1. Sign up to view the full content.
Unformatted text preview: ME 461 Prelab #5
Due at the start of Lab #5 Suggested Reading: Lecture 5 Notes LMD18200 Datasheet LM741 Datasheet Lab 5 manual 1. This circuit has been on a long time. Find the voltages across each element. Show all work. 2. Sketch the LED on‐off curve for the given circuit. Assume R1 = R2 = R3 = 1 kΩ, and that the LED requires a forward bias voltage of 1 V to turn on, and that there is 0.7 V base‐to‐emitter drop and a 0.2 V collector‐to‐emitter voltage drop when the transistor is saturated. Show all work. ME 461 1 Prelab #5 ME 461 2 Prelab #5 3. Design (do not actually build!—you will build the circuit in lab) an op‐amp based circuit that takes as the input an analog voltage in the range of ± 12 V and outputs a gained and shifted analog voltage in the range of 0‐3 V. A good place to start is to study the gain and shift amplifier as shown in the class notes: Analyze this circuit to verify the expression in the lecture notes for the output voltage: Vout = - ⎛ R3
R3 R f ⎞
Vin + ⎜
R2 +R3 R2 +R3 R1 ⎠
⎝ Determine reasonable values for the four resistors. Assume that R2 + R3 = 10 kΩ, and that VCC = 3.6 V? What additional component could you add (and where would you put it) to your design to minimize the effect of high frequency noise in the analog input voltage signal on the output of your circuit. ME 461 3 Prelab #5 4. Suppose a 1 kΩ Sense resistor is connected between the LMD18200 current Sense pin and GND. What is the motor current if the voltage across the Sense resistor is 2.64 V? (Hint: Vsense = isenseRsense and isense = Ksenseimotor, where Ksense is a constant.) 5. Draw a free‐body diagram for the linkage plus DC motor shown below and determine the equation of static equilibrium for the link plus motor. L Assume that motor torque is related to motor current by τmotor = Kmotorimotor , and that you can determine the motor current as you did in the previous question. Show that the voltage across the Sense resistor is directly proportional to the sine of the link angle, Vsense = Ksin θ , where the constant K depends on Ksense, Rsense, mass m, acceleration due to gravity g, link effective length L, and motor constant Kmotor. ME 461 4 Prelab #5 ...
View Full Document
- Spring '08