Quiescent voltage refers to the steady-state voltage level present at a specific point in an electronic circuit when no input signal is applied, and the circuit is in a stable, idle condition. In cybersecurity and hardware security contexts, understanding quiescent voltage is important because attackers may exploit voltage fluctuations or abnormal quiescent levels to detect vulnerabilities, inject faults, or extract sensitive data from hardware devices. Monitoring quiescent voltage helps ensure that circuits operate within safe parameters, reducing the risk of side-channel attacks or hardware malfunctions. Maintaining proper quiescent voltage is essential for both circuit reliability and security.