EE331LE4rev6 - Experiment-4 Experiment-4 FET Driver, Load,...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
Experiment-4 R. B. Darling EE-331 Laboratory Handbook Page E4.1 Experiment-4 FET Driver, Load, and Switch Circuits Introduction The objectives of this experiment are to observe the operating characteristics of inverter circuits which use JFETs and MOSFETs as driver, load, and switch devices, and to observe the effect of differing device parameters on the resulting voltage transfer characteristics (VTCs). The VTCs will be examined both using an oscilloscope and a LabVIEW curve tracer. Precautions Junction field-effect transistors (JFET's) involve only an internal pn-junction and are thus relatively static insensitive and may be handled freely. However, discrete MOSFETs involve a very thin gate oxide layer which may not have any static protection diodes included as part of the device. As a result, the discrete MOSFETs can be very static sensitive and must be treated properly to avoid having to buy replacements. To avoid static discharge damage to the MOSFETs, keep their leads inserted into the black conductive foam whenever possible. Always touch a grounded object, such as the frame of the lab bench, to discharge any built-up static charges from your body before handling the MOSFET. After this, carefully remove the MOSFET from the black foam and insert it into either the curve tracer or the solderless breadboard. Pay particular attention to correctly identifying the leads on the devices. Improper connection of the device is another means in which they can be destroyed. Once the MOSFET is correctly connected into its test circuit, it is reasonably well protected from static, since there now exist resistors or power supply terminals which allow current to flow from lead to lead. As a basic rule, remember that static affects only floating terminals on a device or circuit. Simply connecting these floating terminals to ground with a large value resistor, say 1 M or so, is often sufficient to provide a discharge path for any built-up charges. This experiment will also use standard 4000-series unbuffered CMOS (metal gate) integrated circuits. These IC's have internal diodes to protect the MOSFET gates, but even so, they can still be destroyed by careless handling which may produce an electrostatic discharge (ESD) event. Follow the same precautions as for dealing with a discrete MOSFET. To avoid static discharge damage to the IC's, keep the parts inserted into the black conductive foam whenever it is not being used in a circuit. Alternatively, the pins may be pushed into a small piece of aluminum foil, or the part may be wrapped in the foil, if some conductive black foam is not available. Always discharge any built up static charges from your body by touching a grounded metal object, such as the frame of the lab bench, before
Background image of page 1

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

View Full DocumentRight Arrow Icon
Experiment-4 R. B. Darling EE-331 Laboratory Handbook Page E4.2 handling the ICs. When finished with a given circuit, return the IC to the foam or the foil.
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 09/10/2011 for the course EE 331 taught by Professor Taicheng during the Winter '08 term at University of Washington.

Page1 / 30

EE331LE4rev6 - Experiment-4 Experiment-4 FET Driver, Load,...

This preview shows document pages 1 - 3. Sign up to view the full document.

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