Root on A string
x4546x
C♯7♭5 is the C♯ dominant 7 flat 5 chord. Its notes are C♯, E♯, G and B. It is the same chord as D♭7♭5. A four-note altered dominant. Mute both outer strings.
x4546x
Numbers show frets from the low E string to the high e string; x means don't play that string.
Every C♯, E♯, G and B on the first 12 frets. The filled dots are the root, C♯. Build your own shape from any nearby group.
Other C♯ chords
Other dominant 7 flat 5 chords