Panasonic Electromechanical Relays

Relay contact configurations determine how the relay switches circuits. SPST (Single Pole Single Throw) is the simplest configuration with one set of contacts that either open or close a single circuit - like a simple on/off switch. SPDT (Single Pole Double Throw) has one set of contacts that can switch between two circuits - like a toggle switch that selects between two outputs. DPDT (Double Pole Double Throw) has two sets of SPDT contacts that switch simultaneously - useful for reversing motor direction or switching two circuits at once. The choice depends on your application: SPST for simple on/off control, SPDT for selecting between two circuits, and DPDT for more complex switching requirements.

Choose SPST for simple switching, SPDT for selecting between circuits, DPDT for simultaneous dual switching.

Panasonic relays offer different contact materials optimized for various load types. AgSnO2 (Silver Tin Oxide) is the most common material, offering excellent resistance to welding and material transfer, making it ideal for inductive loads like motors and solenoids. AgCdO (Silver Cadmium Oxide) provides good arc quenching and is suitable for moderate inductive loads, though it contains cadmium which may have environmental restrictions. Au-clad (Gold-clad) contacts provide excellent low-level switching performance and are ideal for dry circuits, signal switching, and precious metal compatibility. For most power applications, AgSnO2 is recommended. For signal or low-level switching, Au-clad is preferred.

Use AgSnO2 for inductive power loads; Au-clad for signal and low-level switching.

The coil voltage of a relay must match your control circuit voltage for proper operation. Panasonic relays are available in standard coil voltages: 5V, 12V, 24V, and 48V DC are most common, with AC coil options also available. Select a coil voltage that matches your control system voltage. Consider the coil power consumption - higher voltage coils typically draw less current for the same power. Ensure your control circuit can provide the required coil current (typically 20-100mA for PCB relays, higher for power relays). Include a flyback diode across the coil for DC relays to protect your switching transistor from inductive kickback. For sensitive applications, consider relays with low coil power consumption.

Match relay coil voltage to your control circuit; include flyback protection for DC coils.

Relay life is specified in two categories: mechanical life and electrical life. Mechanical life refers to the number of operations the relay can perform with no load (or minimal load) applied - this is typically much higher, often 10-50 million operations. Electrical life refers to the number of operations under rated load conditions - this is typically lower, ranging from 100,000 to 1,000,000 operations depending on the load type and current. The electrical life is shorter because switching actual loads causes contact arcing, erosion, and material transfer. Resistive loads provide the longest electrical life, while inductive loads reduce life due to arcing. Capacitive loads can cause high inrush currents that severely reduce contact life. Always consider the load type when evaluating relay life specifications.

Use electrical life rating for loaded applications; mechanical life is for dry switching only.

Yes, Panasonic offers automotive-qualified relays specifically designed for vehicle applications. The TQ series automotive relays are designed to meet automotive standards including vibration resistance, temperature cycling, and electrical load requirements. These relays feature enhanced contact materials and construction to withstand the harsh automotive environment. Standard industrial relays like the ALDP and DSP series are not qualified for automotive use and should not be used in safety-critical vehicle applications. For automotive applications, always select relays specifically designed and qualified for automotive use. Panasonic provides comprehensive documentation and testing data for automotive customers.

For automotive applications, select TQ series automotive-qualified relays only.