Key ratings for the protection decision
The 1.5KE7.5C-B: The reverse standoff voltage is 6.4 V typical, meaning the diode stays high-impedance below that level and only starts conducting when the transient exceeds the 6.75 V minimum breakdown threshold.
Bidirectional and package fit
A single bidirectional channel means the diode protects against both positive and negative transients with one device — useful for AC signal lines or DC rails where reverse polarity is a risk. Housed in a DO-201AA (DO-27) axial-lead through-hole package, it hand-solders easily into a prototype board or production PCB with standard 0.100-inch pitch holes.
Where it fits in the circuit
Marked for general-purpose transient suppression — it is not rated for power-line protection (no internal power-line protection circuitry), so it belongs on signal or low-voltage DC rails rather than mains inputs.