Lab3 - ECE 2B Lab#3 3 Transistors at DC In this lab you will experiment with the three types of transistors JFETs BJTs and MOSFETs Later

Info iconThis preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon
ECE 2B Lab #3 3 Transistors at DC In this lab you will experiment with the three types of transistors: JFETs, BJTs, and MOSFETs. Later coursework (ECE132) will teach you about the physics of how these devices work. Our goal in ECE2 is more practical and focused on using the devices: understanding their current-voltage characteristics, and learning how to configure the circuit environment for the transistor to set the appropriate biasing conditions. In this lab we will not build any clever functional circuits; the goal is simply to learn how to bias transistors correctly. This is always the first step in transistor circuit design, and is crucial to determining the success or failure of the circuit. In fact, most of the mistakes made by beginning students with transistor circuits can usually be traced to incorrect DC biasing. Transistors at DC 1 Pre-lab Preparation 2 Before Coming to the Lab 2 Parts List 2 Background information 3 Transistor Basics 3 Junction Field-Effect Transistors 3 Metal-Oxide-Semiconductor (MOS) Devices 5 Bipolar Junction Transistors 7 In-Lab Procedure 9 3.1 Depletion-mode FETs (JFET) 9 Measuring I-V characteristics 9 JFET Biasing Circuit 10 3.2 Enhancement-mode MOSFETs 11 Gate-Drain I D -V gs Characteristics 11 Four-Resistor Bias Circuit 12 Simple LED Blinker 13 More on Switching 13 3.3 CMOS Circuits 14 3.4 Bipolar Junction Transistors (BJTs) 16 1 © Bob York 2007
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
2 Transistors at DC Pre-lab Preparation Before Coming to the Lab Read through the lab experiment to familiarize yourself with the components and assembly sequence. Calculate the bias resistor values that are required in each of the steps. This will save you time during the lab experiment Each group should obtain a parts kit from the ECE Shop. Parts List Use stocked cabinet in lab and the bench decade box for any required resistors Laboratory #3 Intro to Transistors Qty Description 2 2N5485 n-ch JFET 2 2N7000 NMOS 2 2N3904 NPN BJT 2 2N3906 PNP BJT 1 CD4007 CMOS pair/inverter 1 1uF capacitor (electrolytic, 25V, radial) 2 Red LED (20mA) © Bob York 2007
Background image of page 2
Background information 3 Background information Suggested background reading: Sedra & Smith: Sections 4.2-4.5, 5.2-5.5 (excellent stuff on MOS and BJTs, although somewhat more rigorous in detail than we need here). Transistor Basics Familiar two-terminal components such as resistors, capacitors, and diodes, are defined electrically by the current-voltage characteristic, , as in Figure 3-1a. Transistors differ in that they have a third terminal, shown conceptually in Figure 3-1b, which serves as a control point to manipulate the current flow through the device. The ability to control the current flow through one part of the device using a separate electrical signal is what makes transistors useful. () IV There are two main types of transistors that are grouped according to whether the I-V characteristics depend on the voltage or current at the control terminal. In “Field-Effect Transistors”, or FETs, the I- V curve is a function of the voltage (electric field) at the control terminal. In
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 4
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 12/02/2009 for the course ECE 2B taught by Professor York during the Spring '07 term at UCSB.

Page1 / 17

Lab3 - ECE 2B Lab#3 3 Transistors at DC In this lab you will experiment with the three types of transistors JFETs BJTs and MOSFETs Later

This preview shows document pages 1 - 4. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online