Tag: JFET Circuits
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5.4 Active-mode Operation (JFET)
JFETs, like bipolar transistors, are able to “throttle” current in a mode between cutoff and saturation called the active mode. To better understand JFET operation, let’s set up a SPICE simulation similar to the one used to explore basic bipolar transistor function: Spice Simulation of a JFET Operation jfet simulation vin 0 1 dc 1…
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5.3 Meter Check of a Transistor (JFET)
Testing a JFET with a multimeter might seem to be a relatively easy task, seeing as how it has only one PN junction to test: either measured between gate and source, or between gate and drain. Testing Continuity of an N-channel JFET Testing continuity through the drain-source channel is another matter, though. Remember from the…
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5.2 The Junction Field-effect Transistor (JFET) as a Switch
Like its bipolar cousin, the field-effect transistor may be used as an on/off switch controlling electrical power to a load. Let’s begin our investigation of the JFET as a switch with our familiar switch/lamp circuit: Remembering that the controlled current in a JFET flows between source and drain, we substitute the source and drain connections…
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5.1 Introduction to Junction Field-effect Transistors (JFET)
A transistor is a linear semiconductor device that controls current with the application of a lower-power electrical signal. Transistors may be roughly grouped into two major divisions: bipolar and field-effect. In the last chapter, we studied bipolar transistors, which utilize a small current to control a large current. In this chapter, we’ll introduce the general…