` CREATIVE COMPUTING VOL. 9, NO. 4 / APRIL 1983 / PAGE 218`

 Simulated circuits. (computer programs) David A. Holko. Simulated Circuits Physics teachers sometimes have difficulty setting up electrical equipment for labs. Faulty meters, short wires, dead batteries, power supplies without fuses, loose connections, and wrong size resistors are just some of the reasons for the difficulty. The following program simulates circuits for experiments on series, parallel, and parallel-series resistance circuits. Using a graphic representation of the circuit, meters, and resistors the student can conduct measurements of voltage and amperage by keying changes in the values of resistance or source EMF. The computer shows corresponding changes on the symbolic circuit. Figures 1, 2, and 3 show the circuits drawn by the computer on the video display. In Figure 1, three asterisks are shown below the EMF = 12 VOLTS. As the computer runs the program, the asterisks will appear sequentially below R1, R2, R3, and EMF. If the I key is depressed while they are as shown in Figure 1, the source voltage is increased. If the D key is depressed, the source voltage is decreased. Once a change has been made in resistance or voltage the simulated meters will show related changes. Note: To avoid errors caused by division by zero, the values R1 = 100 ohms, R2 = 100 ohms, and EMF = 12 volts are assigned if R1, R2, or EMF are changed to zero or less. I hope these simulations stir some of your own ideas for other simulations. These simulations will simplify your labs, and allow your students to spend less frustrating time in the lab. They will also allow them more time to analyze circuit characteristics. If nothing else, with this program, you can be sure your students won't be electrocuted or blow a fuse. Photo: Figure 1. Photo: Figure 2. Photo: Figure 3.