Question

Could use some guidance and help on this Ammeter lab. Spe ifically on how to build the circuit on a bread board.

80% . 1:30 PM engrcir-1-7.pdf Ammeter Introduction Th c purpose of this lab is to design and build our own analog ammeter The D'Arsonval movement is the key component that allows us to build an analog voltmcter and ammeter. This movement contains a coil and magnet that sense current flowing through the movement. When current flows through the movement, the indicator needle moves. The amount of current required to make the needle move to 100% varies per movement. Movements are typically 100uA. 1 mA, or 10mA full scale movements. The movements in our lab are 100uA. Section 3.5 of the Nilsson textbook explains in more detail how these movements work. To complete our design we need to know how much current makes the needle deflect to full scale and what the load resistance of the movement is. When placed into a circuit the movement will represent a resistor and inductor in that circuit. For our purposes we only care about the resistance of the movement and not the inductancc. When analyzing circuits involving this movement, the movement is simply replaced by this load resistance in the schematic. This makes analysis of the circuit much simpler. The movements in lab are nominal 100uA movements and have a nominal load resistance of about 2.2k2. The analog movements will be used in conjunction with resistors to create an ammeter that has a 0- 10mA range. The meter (Volt or Amp) consists of the analog movement and additional resistors. Think of placing your complete circuit in a box. The user will be able to see the meter and terminals of your meter. The ammeter will have 2 terminals: common, current input. A block diagram of the meter is shown in Figure1. The resistor network and proper conncctions are what you must design. Resistor Network +10mA Movement Ammeter Figure : Block diagram of Ammeter Our lab setup only contains one voltage source and no current sources. In order to test your ammeter we must find a way to convert voltage to current. The resistor does this naturally via Ohm's law. We are going to use a variahle resistor (potentiometer) to convert the voltage of the power supply into a current that we can control. The schematic symbol for the pot is shown in Schematic l-a. Terminals 1 and 3 are in fixed positions, while terminal 2, the wiper, is variable. Turning the knob or screw on the pot causes the location of ENGR221 Electrical Circuits I Farrell 02/09/15 Ammeter terminal 2, the wiper, to move relative to terminal 1 and 3. Schematic 1-b shows a simple resistor model of a pot. The total resistance of the pot is always measured between terminals 1 and 3, R13 R13 R12+R23. As the knob is turned and the wiper moves, R12 and R23 change values. However R13 doesn't change. For a 100? pot. R 13 is 100?. R12 and R23 range from 0? to 100?. Pin 2 is

Answer 1

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