xkcd.WTF!?

Explanation ➲

This comic contains several symbols used in circuit diagrams. Each is labeled with a larger object that the symbol looks like a drawing of, rather than the electrical component it actually represents. Randall has previously depicted distorted uses, depictions, and labeling of the standard US-form electronic symbols in comics such as 730: Circuit Diagram.

Symbol	Randall's Description	Explanation
Switch	Drawbridge	The symbol represents a physical on/off switch in a circuit, but also resembles a drawbridge. A switch functions the exact same as a drawbridge, impeding electrons' flow when it is open. The purpose of a drawbridge is to allow people to cross who are impeded when the bridge is raised.
Capacitor	Overpass	A capacitor is a component that can be used to hold electric charge, but the symbol for it looks a bit like a depiction of a highway overpass, where one road or track passes over another, allowing the paths to cross without intersecting. The distinction between an overpass and underpass is largely one of perspective, as when one road (or footpath, or animal migration route) goes over, the other is going under. Because a capacitor does not indicate a place of intersection of separate electrical circuits, any interpretation of a meaningful connection between an overpass and a capacitor is tenuous at best. A capacitor is an electrical component that alternating current can get across, but direct current can't. This could be like how heavy trucks are not allowed on overpasses. However, this still only involves one electrical pathway.
Ground	Pogo Stick	This symbol represents a connection to "ground" or "earth", the common baseline voltage or safe current sink for various circuits (e.g., against which an aerial signal can be compared). If the horizontal lines are taken as motion lines or a spring, it might look like a stylized pogo stick.
Resistor (ANSI)	Earthquake	A resistor is a component that reduces current flow in a circuit. There are two main symbols used: an IEC-style 'box' or, like here, the ANSI zig-zagged line. In this case, it also looks somewhat like the marks an earthquake makes on a seismograph and/or the 'rucks' of the ground (especially asphalt roads) that might result from underlying tectonic movements.
Inductor	Sheep	Inductors create a magnetic field when current passes through them, and generally consist of a coil of wire, which the symbol reflects. The symbol seems in this case to be interpreted like the fluffy wool of a sheep.
Transformer	Two sheep in love, trapped on opposite side of a fence.	A transformer consists of two (or more) induction coils, for input and output(s), and a common core to mediate the transfer of power across the gap. The curly loop symbols of the symbol have already been claimed to resemble sheep, and the straight line (which is the core) now represents a fence separating two sheep who nonetheless wish to be together.
Battery	Battery	Not a joke, this is a typical symbol for a battery (which provides voltage to a circuit),[citation needed] or other form of voltaic pile. Its inclusion here is simply as the set-up for the following joke symbols.
Battery (sorted)	Baertty	Randall may have mapped the characters "tt" to the first short line and "er" to the following long line in the original symbol, having had "ba" and "y" assigned to the long and short "T" shapes that form the connections to the rest of the circuit. Rearranging the symbolic verticals as long-long-short-short, as he has done in this (fictional) symbol, thus puts "er" in front of "tt". Another sorting paradigm is that, after the initial 'B', the remaining letters are arranged in alphabetical order, left to right. Similarly, after the first horizontal line in the symbol, the other line segments are arranged by decreasing vertical height (left to right).
Battery, with far too many short lines	Battttttttttttery	The only other fictional symbol. Which, by the same established naming rules, means that the name is spelled with six "tt"s instead of just the single pair.
Photodiode	Check out this really cool diode	A photodiode generates, or allows to pass, a current in response to light. The symbol is related to the standard diode with the arrows pointing at it representing the light which activates its behavior. In this case, Randall instead pretends that the arrows are pointing at it to draw attention to it because it's "really cool" (it is!).
Oscillator	Wave Pool	An oscillator generates signals that oscillate at a given frequencies, for use in other circuitry, and one symbol used for one (in reality, built from a number of components in their own right) is this symbol. Waves in water are a type of oscillation that may be more familiar to most people than waves of electricity. A wave pool is in fact the result of a type of (mechanical) oscillator, and rarely has electricity running through it.[citation needed]
Transistor	Trolley Problem	A transistor will switch on current flow across one of a pair of connections, depending upon the input from an input one. Randall likens this to the ability to use points to switch the destination of a trolley from one track to another, as protagonists are invited to do in the various versions of the trolley problem. The symbol also somewhat resembles the usual pictorial depiction of the problem. However, single transistors are not generally used to resolve ethical dilemmas.[citation needed]
A circle with an A [In the title text]	The circuit has committed a sin and has been marked as punishment	Circles with letters are usually some special components, as also with the oscillator's glyph. In this case the "A" stands for ammeter, a device used to measure electric current (an "ampere meter"). This is conflated with the practice of branding the 'guilty', or requiring them to display their crime for a period of penance. For example, in The Scarlet Letter, a historical novel by Nathaniel Hawthorne, the protagonist must wear an A to mark her as an adulteress.