This preview shows pages 1–3. Sign up to view the full content.
This preview has intentionally blurred sections. Sign up to view the full version.View Full Document
Unformatted text preview: ECE 2100 Laboratory 1 The main purpose of this lab is to familiarize you with the lab work benches and to demonstrate the most basic functions of the measurement apparatus. Additionally you will verify Ohms Law and the voltage and current divider principles. Use of the protoboard, digital multimeter (DMM), and power sup- ply (PS) It will take some time to develop your skills in protoboarding a circuit. You must first understand how the slots for wires and circuit components are electrically connected. This is shown in the figure below. The protoboard has two main areas: the (horizontal) power and ground dis- tribution rails and the main circuit area (with vertical shorts). The power distribution rails are primarily for connecting the power supply voltages and ground connections to various parts of the circuit by means of short connect- ing wires. Such a string of connected slots is called a power bus. This is crucial for laying out complicated circuits in a logical and neat fashion. It is standard convention to use one of the top rails for positive dc voltage and the adjacent one for ground (zero volts) connections. The bottom rails are for negative dc voltage and another adjacent ground. Access to the ground rails needs to be convenient; that is why we usually use two rails. The two halves of the upper two and lower two rails are not electrically connected to each other, since there is a gap at the center of the protoboard. In many applica- tions we need to jump this gap with a short piece of wire so that power and ground are readily available everywhere. Thus, to supply power or connect ground to components such as transistors and operational amplifiers, all we need to do is to jump a short piece of wire from the power or ground rail to the component. All circuit components go in the two sections consisting of five vertical holes each ( a- e and f- j ). These two sections are electrically isolated (i.e., 1 a- e are NOT connected to f- j ) but a- e are connected to each other and f- j are electrically connected to each other. The columns 1 - 64 are NOT electrically connected to each other. In protoboarding a circuit it is good practice to layout components and wires in a rectilinear fashion in which all components and wires run either vertically or horizontally but not at an angle or with big loops. Poor protoboarding technique can result in poorly functioning circuits due to cross talk from capacitive and inductive coupling from crossed wires and loopy wiring. You should take good care to lay out your circuit as neatly as you can with good utilization of protoboard space. Messy bent wires on resistors and capacitors make it difficult to read the circuit. If you find it difficult to insert components into the slots, a needle nose pliers can help a lot. It is also good practice to use several different colors of 22 gauge wire (spooled wire with solid colors) with a consistent color scheme (e.g., red for +power, green for -power, and black for ground). Also, different colors make it easiergreen for -power, and black for ground)....
View Full Document
This note was uploaded on 03/31/2009 for the course ECE 210 taught by Professor Staff during the Spring '08 term at Cornell University (Engineering School).
- Spring '08