Identify this component ?

ryjord88 · ‎2026-01-21

Hi I have a diode which i believe is a zener diode as the marking on the bottom line is z

the 3 lines are as follow

top line= st and a 6 at the end

middle line= CU6

bottom line= z 721

i need to know what diode it is and what voltage and current value it is,

thanks in advance

Peter BENSCH · ‎2026-01-22

600W is the peak pulse power, the SMBJ16A is a unidirectional TVS with VRM = 16V. If you need to repair it, you should use the same performance class, i.e. TVS 600W, 16V, unidirectional, Package SMB. If you want to use exactly the same type, simply get the SMBJ16A (not SMBJ16CA).

Good luck!
/Peter

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ryjord88 · ‎2026-01-21

Peter BENSCH · ‎2026-01-22

Welcome @ryjord88, to the community!

Although it is difficult to read due to the blurred photo, it looks like the marking CUG, which stands for the SMBJ16A.

Hope that helps?

Regards
/Peter

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ryjord88 · ‎2026-01-22

yes it was a nightmare trying to focus it, even under my magnifying lamp it was hard to read, so what voltage and amps should this protect against? ive had a quick check up and can see 600w but is there a fixed voltage or us there variations to the component?

Peter BENSCH · ‎2026-01-22

600W is the peak pulse power, the SMBJ16A is a unidirectional TVS with VRM = 16V. If you need to repair it, you should use the same performance class, i.e. TVS 600W, 16V, unidirectional, Package SMB. If you want to use exactly the same type, simply get the SMBJ16A (not SMBJ16CA).

Good luck!
/Peter

In order to give better visibility on the answered topics, please click on Accept as Solution on the reply which solved your issue or answered your question.