Is 51000 ohms a standard valve for 5 percent resistor?

Yes, 51,000 ohms (or 51 kΩ) is a standard value for a 5% tolerance resistor. Resistors are often available in E12 and E24 series, where the E12 series includes values like 10k, 22k, 47k, and 100k, with 51k being a standard increment in the E24 series. Therefore, it is commonly used in electronic circuits where a specific resistance is required within that tolerance range.