Examples of Engineering Symbols Table

Figure

Electrical

• Fixed resistor: A horizontal line extends rightwards, then zig-zags up and down with a medium frequency before becoming horizontal again.
• Variable resistor: A horizontal line extends rightwards then zig-zags up and down with a high frequency before becoming horizontal again. An arrow above the zig-zag comes in from the right and turns down, pointing at the zig-zag.
• Diode: A horizontal line extends rightwards before terminating on the left side of a rightward pointing triangle. After a short space, there is a short vertical line. Another horizontal line extends rightwards from the center of the vertical line.
• Capacitor: A horizontal line extends rightwards before terminating on the left side of a short vertical line. After a short space, there is a semicircle that opens to the right. Another horizontal line extends rightwards from the center of the inner edge of the semicircle.
• LED: A horizontal line extends rightwards before terminating on the left side of a rightward pointing triangle. After a short space, there is a short vertical line. Another horizontal line extends rightwards from the center of the vertical line. Two arrows point down and right, one beginning just below the triangle and one just below the vertical line.
• Solar cell: A horizontal line extends rightwards before terminating on the left side of a rightward pointing triangle. After a short space, there is a short vertical line. Another horizontal line extends rightwards from the center of the vertical line. Two arrows point up and left, one pointing towards the triangle and one towards the vertical line.
• Photo resistor: A horizontal line extends rightwards, then zig-zags up and down with a medium frequency before becoming horizontal again. A circle encloses the zig-zags and an arrow points up and right inside the circle across the zig-zags.
• Lamp: A horizontal line extends rightwards, then turns upwards and forms a small loop before continuing rightwards horizontally. A circle encloses the loop and a portion of the horizontal line on either side of the loop.
• Battery: A horizontal line extends rightwards and terminates at a longer vertical line. Continuing rightwards, there is a space, a shorter vertical line, a space, a longer vertical line, a space, a shorter vertical line, a space, a longer vertical line, a space, a shorter vertical line, and a horiztonal line that extends rightwards. A plus sign lies just to the left of the leftmost vertical line above the horizontal wire.
• Op-amp: Two parallel horizontal lines extend rightwards into the left side of a rightward pointing triangle. Another horizontal line extends rightwards from the right vertex of the triangle. A minus sign lies inside the triangle in the top left corner and a plus sign lies in the bottom left corner.
• Meter: An outer circle contains the top segment of another circle that extends from the bottom left to the bottom right of the outer circle. An arrow inside the outer circle extends up and left from the inner circle segment.
• Speaker: Two vertical lines extend from the top and bottom of a small square. Two lines extend rightwards from the right corners of the square, one going upwards and one going downwards. The lines connect to either end of a longer vertical line.
• Single-phase motor: Two curved arrows point towards a circle. One arrow is labeled T₁ and is on the top left and the other arrow is labeled T₂ and is on the top right.

Logic Gate

• AND (Output if all control input signals are on): Two parallel horizontal lines extend rightwards into a vertical line. Horizontal lines on either end of the vertical line extend rightwards before curving towards each other until they meet at another horizontal line that extends rightwards.
• OR (Output if any one of the control inputs is on): Two parallel horizontal lines extend rightwards into a vertical line that curves leftwards on the top and bottom. Lines on either end of the vertical line extend rightwards and curve towards each other until they meet at another horizontal line that extends rightwards.
• NOT (Output if single control input signal is off): A horizontal line extends rightwards into the left side of a rightward pointing triangle. A small circle lies at the tip of the right vertex of the triangle. Another horizontal line extends rightwards from the circle.
• NAND (Output if all control input signals are off): Two parallel horizontal lines extend rightwards into a vertical line. Horizontal lines on either end of the vertical line extend rightwards before curving towards each other until they meet at a small circle. Another horizontal line extends rightwards from the circle.
• NOR (Output if all control input signals are off): Two parallel horizontal lines extend rightwards into a vertical line that curves leftwards on the top and bottom. Lines on either end of the vertical line extend rightwards and curve towards each other until they meet at a small circle. Another horizontal line extends rightwards from the circle.

Plumbing and Piping

• Standard bathtub: A rectangle contains a smaller rectangle with curved corners. A small circle lies inside the smaller rectangle near the right end.
• Oval bathtub: A rectangle contains an oval. A small circle lies inside the oval near the right end.
• Whirlpool bath: A rectangle contains a shape where the left half of the shape is a smaller rectangle with curved corners and the right half of the shape is a slightly larger rectangle with curved corners. A small circle lies inside the larger inner rectangle near the right end.
• Shower stall: A square contains a smaller square. The smaller square contains lines that go from the top left and top right corners to the bottom right and bottom left corners, respectively.
• Floor drain: A small circle.
• Floor sink: A square contains lines that go from the top left and top right corners to the bottom right and bottom left corners, respectively.
• Drinking fountain: A square with curved corners is labeled DF.
• Chilled drinking water supply: Horizontal lines extend left and right from the letters DWS.
• Chilled drinking water return: Horizontal lines extend left and right from the letters DWR.
• Hot water: A repeating inline pattern of a longer horizontal segment followed by two shorter horizontal segments.
• Hot water return: A repeating inline pattern of a longer horizontal segment followed by three shorter horizontal segments.
• Straight-size cross: A vertical line and a horizontal line intersect at their midpoints. The horizontal line terminates at either end at a pair of short parallel vertical lines and the vertical line terminates at either end at a pair of short parallel horizontal lines.
• 45 degree elbow: A vertical line extends upwards from a pair of short horizontal lines, bends to the right at a 45 degree angle, and terminates at a pair of short parallel lines perpendicular to it.
• 90 degree elbow: A vertical line extends upwards from a pair of short horizontal lines, bends to the right at a 90 degree angle, and terminates at a pair of short parallel vertical lines.
• Connecting pipe joint: A horizontal line extends through the midpoint of two short parallel vertical lines.
• Expansion joint: Two horizontal lines beginning inside a rectangle extend outwards through the midpoint of the left and right sides of the rectangle. The horizontal lines each go through the midpoint of vertical lines just outside of the rectangle.
• Straight-size tee: A vertical line extends upwards from the midpoint of a horizontal line. The horizontal line terminates at either end at a pair of short parallel vertical lines and the top end vertical line terminates at a pair of short parallel horizontal lines.
• Gate valve: A horizontal line extends rightwards through the midpoint of a vertical line and into the left side of a rightward pointing triangle. The left vertex of a leftward pointing triangle touches the right vertex of the rightward pointing triangle. Another horizontal line extends rightwards from the right side of the leftward pointing triangle through another vertical line. A short vertical line extends upwards from the point where the triangles meet and terminates at a short horizontal line.
• Globe valve: A horizontal line extends rightwards through the midpoint of a vertical line and into the left side of a rightward pointing triangle. The left vertex of a leftward pointing triangle touches the right vertex of the rightward pointing triangle. Another horizontal line extends rightwards from the right side of the leftward pointing triangle through another vertical line. A solid circle lies on the point where the triangles meet.