The HS12SP is a bulk-resistance type relative humidity sensor that provides variable impedance output in response to adsorbed water within its proprietary thin-film polymer. The sensor operates by applying an interdigitated electrode to the polymer, where chemical functional groups disassociate into ionic groups in the presence of water, increasing electrical conductivity when excited by low voltage alternating current. It features an inverse exponential humidity response curve with exceptional linearity, low hysteresis, and fast response time, operating across a humidity range of 30–90% RH and temperature range of 0–50°C. The sensor exhibits a nominal impedance of 60 kO at 25°C and 50% RH, with a tolerance range of 42–78 kO, and operates at a rated working voltage of AC 1V (50 Hz–1 kHz) with minimal power consumption of 0.3 mW. Its simple signal conditioning requirements, excellent interchangeability, and small form factor make it ideal for HVAC controls, medical devices, data loggers, automotive climate control, and environmental monitoring applications.