Figure 4.21. This figure shows the schematic symbols for six types of field effect transistors. Each of the 6 descriptions has been written to stand alone.

Number 1, the N channel junction FET. There is a circle. A line crosses the perimeter from the left outside. It would go through the center if it were that long, but it isn't. It ends at about one third the way across the circle in an arrowhead. The arrowhead points to the right. There is a vertical line touching the point of the arrowhead. This line is almost as long as it can be without touching the perimeter. At about two thirds the way across the circle a line begins below and outside and goes up crossing the perimeter. At about one third the way up it turns to the left and ends when it touches the vertical line below its center. It does not touch at the lower end of the line but a little way from the bottom. Another line starts outside and above the circle and directly above the one that started from below. It goes down and crosses the perimeter. It turns to the left at about two thirds of the height and ends when it touches the vertical line above its center. This line does not touch at the end of the vertical line but a little way from the top end. The connection on the left is the gate, the one below is the source and the one above is the drain. End of number 1.

Number 2, the P channel junction FET. There is a circle. A line crosses the perimeter from the left outside. It would go through the center if it were that long, but it isn't. It ends at about one third the way across the circle. There is an arrowhead on this line with its point just inside the perimeter. The arrowhead points to the left. There is a vertical line touching the line that comes in from the left. This line is almost as long as it can be without touching the perimeter. At about two thirds the way across the circle a line begins below and outside and goes up crossing the perimeter. At about one third the way up it turns to the left and ends when it touches the vertical line below its center. It does not touch at the lower end of the line but a little way from the bottom. Another line starts outside and above the circle and directly above the one that started from below. It goes down and crosses the perimeter. It turns to the left at about two thirds of the height and ends when it touches the vertical line above its center. This line does not touch at the end of the vertical line but a little way from the top end. The connection on the left is the gate, the one below is the source and the one above is the drain. End of number 2.

Number 3, the N channel depletion mode MOSFET. There is a circle. Imagine a capitol letter T turned on its side with the foot of the T to the left. The staff of the T crosses the perimeter of the circle with the head inside the circle. There is a vertical line to the right of the T but not touching it. This line is slightly to the left of the center of the circle and almost as long as it can be without touching the inside of the circle. At about two thirds the way across the circle a line begins below and outside and goes up crossing the perimeter. At about one third the way up it turns to the left and ends when it touches the vertical line below its center.. It does not touch at the lower end of the line but a little way from the bottom. Another line starts outside and above the circle and directly above the one that started from below. It goes down and crosses the perimeter. It turns to the left at about two thirds of the height and ends when it touches the vertical line above its center. This line does not touch at the end of the vertical line but a little way from the top end. Another line starts at the center of the vertical line and goes to the right until it is even with the lines coming up from below and down from above. It turns down and joins the line coming up from below. The horizontal part of this line has an arrowhead pointing to the left. The connection on the left is the gate, the one below is the source and the one above is the drain. End of number 3.

Number 4, the P channel depletion mode MOSFET. There is a circle. Imagine a capitol letter T turned on its side with the foot of the T to the left. The staff of the T crosses the perimeter of the circle with the head inside the circle. There is a vertical line to the right of the T but not touching it. This line is slightly to the left of the center of the circle and almost as long as it can be without touching the inside of the circle. At about two thirds the way across the circle a line begins below and outside and goes up crossing the perimeter. At about one third the way up it turns to the left and ends when it touches the vertical line below its center.. It does not touch at the lower end of the line but a little way from the bottom. Another line starts outside and above the circle and directly above the one that started from below. It goes down and crosses the perimeter. It turns to the left at about two thirds of the height and ends when it touches the vertical line above its center. This line does not touch at the end of the vertical line but a little way from the top end. Another line starts at the center of the vertical line and goes to the right until it is even with the lines coming up from below and down from above. It turns down and joins the line coming up from below. The horizontal part of this line has an arrowhead pointing to the right. The connection on the left is the gate, the one below is the source and the one above is the drain. End of number 4.

Number 5, the N channel enhancement mode MOSFET. There is a circle. Imagine a capitol letter T turned on its side with the foot of the T to the left. The staff of the T crosses the perimeter of the circle with the head inside the circle. There is a dashed vertical line to the right of the T but not touching it. This line consists of 3 dashes, one at the top, one in the center, and one at the bottom. This line is slightly to the left of the center of the circle and almost as long as it can be without touching the inside of the circle. At about two thirds the way across the circle a line begins below and outside and goes up crossing the perimeter. At about one third the way up it turns to the left and ends when it touches the lower dash of the vertical line. Another line starts outside and above the circle and directly above the one that started from below. It goes down and crosses the perimeter. It turns to the left at about two thirds of the height and ends when it touches the upper dash of the vertical line. Another line starts at the center of the center dash of the vertical line and goes to the right until it is even with the lines coming up from below and down from above. It turns down and joins the line coming up from below. The horizontal part of this line has an arrowhead pointing to the left. The connection on the left is the gate, the one below is the source and the one above is the drain. End of number 5.

Number 6, the P channel enhancement mode MOSFET. There is a circle. Imagine a capitol letter T turned on its side with the foot of the T to the left. The staff of the T crosses the perimeter of the circle with the head inside the circle. There is a dashed vertical line to the right of the T but not touching it. This line consists of 3 dashes, one at the top, one in the center, and one at the bottom. This line is slightly to the left of the center of the circle and almost as long as it can be without touching the inside of the circle. At about two thirds the way across the circle a line begins below and outside and goes up crossing the perimeter. At about one third the way up it turns to the left and ends when it touches the lower dash of the vertical line. Another line starts outside and above the circle and directly above the one that started from below. It goes down and crosses the perimeter. It turns to the left at about two thirds of the height and ends when it touches the upper dash of the vertical line. Another line starts at the center of the center dash of the vertical line and goes to the right until it is even with the lines coming up from below and down from above. It turns down and joins the line coming up from below. The horizontal part of this line has an arrowhead pointing to the right. The connection on the left is the gate, the one below is the source and the one above is the drain. End of number 6.

End verbal description.
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