Voltage-Current Characteristics of Electromagnetic Relay

 The volt-ampere characteristic curve of an electromagnetic relay mainly exhibits nonlinear characteristics, which are caused by the magnetic saturation of the core.

1. Pull-in characteristic: As the coil voltage gradually increases, the coil current also increases, but not in a linear relationship. When the voltage reaches the pull-in voltage, the relay pulls in rapidly.

2. Release characteristic: As the coil voltage gradually decreases, the coil current also decreases. When the voltage drops to the release voltage, the relay releases.

3. Hysteresis characteristic: The pull-in voltage is usually higher than the release voltage, forming a hysteresis loop, which is caused by the magnetic hysteresis of the core and mechanical friction.