7811

7811 is typically a fixed-output positive voltage regulator in the 78xx series, delivering a regulated +11 volts at its output. It is a three-terminal device designed to provide a stable rail from a higher, unregulated input voltage, commonly used in power supplies and electronic equipment. The device can supply varying current up to a specified limit, depending on the package, manufacturer, and thermal conditions.

In the most common through-hole package (TO-220) with the front facing you, the pins are arranged input, ground, and output from left to right. Some manufacturers use identical pinouts, but pin configuration can vary among different variants and packaging, so the exact datasheet should be consulted before use. The regulator requires an input voltage higher than the intended output by a certain margin (dropout voltage), and its governing parameters include line regulation, load regulation, and maximum output current.

Typical protections found in 7811 regulators include thermal shutdown and current limiting to prevent damage during short circuits or overheating. The device dissipates heat according to the formula (Vin − Vout) × Iout, making adequate heat sinking important when drawing significant current.

Applications for the 11-volt regulator include providing a stable supply rail for analog circuitry, sensors, and some microcontroller systems that require an 11 V input stage. While widely available, the 11 V variant is less common than other fixed regulators like 7805 or 7812. The 7811 has a direct counterpart in the negative family as 7911, which provides −11 V.

Variants and equivalents (for example LM7811, KA7811, MC7811) may differ in packaging and thermal characteristics but share the same fixed 11 V output concept.