I need to know the type and value of these two diodes, in order to buy two equivalent ones. Can you help me to find it out please?

The diode with the yellow stripe has no markings, while the other one is marked 5.1 B2.

yellow stripe

black stripe "5.1 B2" marking

  • 3
    \$\begingroup\$ Can you give a clue as to their previous employment? i.e., What were they pulled out of and what were they supposed to do? 5.1 is a standard Zener diode voltage. \$\endgroup\$
    – Transistor
    Feb 24, 2021 at 17:08

1 Answer 1


The diode with the yellow band is probably an ordinary 1N4148.

Advice check: https://www.alldatasheet.com/view.jsp?Searchword=U5.1B2&sField=3

This information should be used with caution, the information @transistor asked for helps for a substantiated answer.


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