Laboratory Exercise 2: Verifying Kirchhoff's Laws in Electric Circuits, Schemes and Mind Maps of Law

Download Laboratory Exercise 2: Verifying Kirchhoff's Laws in Electric Circuits and more Schemes and Mind Maps Law in PDF only on Docsity! ECE 231 Laboratory Exercise 2 Kirchhoff’s Laws 1 R. Frank Smith, Cal Poly Pomona University, 2016 ECE 231 Laboratory Exercise 2 – Kirchhoff’s Laws Laboratory Group (Names) _______________ ______________ _______________ OBJECTIVE  Verify Kirchhoff’s voltage law  Verify Kirchhoff’s current law  Gain experience in using both an ammeter and voltmeter  Construct two (2) circuits as shown in Figure 1 and Figure 2. Figure 1. Schematics for verifying Kirchhoff's Laws EQUIPMENT REQUIRED  ECE 231 Circuit Board (In Stock room)  Two banana cables (one for DC power supply and one for DMM)  One lot of colored clip leads (students must supply their own clip leads)  DMM (digital multimeter)  DC power supply BACKGROUND Gustav Kirchhoff first described his laws in 1845. His first law KCL simply stated is that current into a node must equal the current leaving a node where a node is the point where two or more components are connected together. In Figure 1 above, the three currents I1, I2, and I3 leave the top node and go through the three resistors and then merge on the ground circuit. The R1 R2 R3 R3R2R1 V1 10Vdc V1 10Vdc 0 0 Ammeter Ammeter I Parallel Circuit Series Circuit 1 2 I 3 I B A E D C ECE 231 Laboratory Exercise 2 Kirchhoff’s Laws 2 R. Frank Smith, Cal Poly Pomona University, 2016 voltage across any parallel resistors is always the same. Current through any resistor can be determined by using Ohm's law. 𝐼 = 𝑉 𝑅 = 𝑉𝑜𝑙𝑡𝑎𝑔𝑒 𝑎𝑐𝑟𝑜𝑠𝑠 𝑎 𝑟𝑒𝑠𝑖𝑠𝑡𝑜𝑟 𝑅𝑒𝑠𝑖𝑠𝑡𝑎𝑛𝑐𝑒 or by measuring the current through each resistor using an ammeter. Kirchhoff's Current Law (KCL) ∑ 𝑰𝒌 = 𝟎𝒏 𝒌=𝟏 where is the n is the number of branches at a node. Kirchhoff's Voltage Law (KVL) ∑ 𝑽𝒌 = 𝟎𝒏 𝒌=𝟏 where is the n is the number of components (resistors and voltage sources) in a loop. Kirchhoff's second law is like going on a hike from your car around a mountain (independent of path). When you get back to your car, your net change in potential energy is zero. No matter how you measure voltages around a circuit, when you return to your starting point the change in voltage is zero. Figure 2. Protoboard connection for the series circuit PROCEDURE