Standard way to represent signed integers in binary.
Negative numbers are represented by inverting all bits and adding 1. An n-bit range is -2ⁿ⁻¹ to 2ⁿ⁻¹-1. Addition works the same for signed and unsigned, with overflow detection by sign bits. Sign extension preserves value when widening.
8-bit -5 = 11111011.
Two's complement lets a processor perform signed arithmetic with the same adder as unsigned arithmetic, so it is used in almost every processor.
Standard way to represent signed integers in binary.
Two's complement lets a processor perform signed arithmetic with the same adder as unsigned arithmetic, so it is used in almost every processor.
Invert all bits and add one, so minus five in 8-bit is 11111011.
From minus 128 to plus 127.
Typical applications include checking the range of an 8-bit signed sensor value, understanding why an overflow flips a positive result to negative and converting a negative temperature reading stored as a byte.
Study "Number conversions" first (topic 35 of 104 in Electronics & Embedded). It covers the groundwork this topic builds on.
MSB indicates sign. Single zero representation. Subtraction becomes addition.
8-bit -5 = 11111011.
The next topic is "Logic gates", which builds directly on this one.
It is classed as Beginner in Electronics & Embedded (topic 36 of 104). It is an entry-level topic. It relies only on basic school mathematics and the ideas introduced earlier in this discipline.
Want to practise? Open the interactive course for quick checks, quizzes, simulations and progress tracking.