Relay Coil Calculator
Calculate relay coil with this free online tool
Coil Characteristics
Coil Current
30.00 mA
I = V/R = 12V / 400Ω
Coil Power
360.00 mW
P = V²/R = 12² / 400
Recommended Transistor (BJT)
Min V_CE (collector-emitter)
>24.0 V
≥ 2× coil voltage
Min I_C (collector current)
>60.0 mA
≥ 2× coil current
Min Power Dissipation
>540 mW
≥ 1.5× coil power
Suggested transistors:
2N2222A, BC547, 2N3904
Flyback Diode
Min Voltage Rating
>24.0 V
Min Current Rating
>45.0 mA
Suggested: 1N4001, 1N4007 (connect cathode to V+, anode to collector)
Base Resistor (Arduino/MCU @ 5V)
Base Resistor Value
7.17 kΩ
Rb = (V_GPIO - V_BE) / (I_C_desired / h_FE)
Assumed h_FE = 100, V_BE = 0.7V
Nearest Standard Value
7 kΩ
Base resistor power: 2.58 mW
Dapatkan hasil yang tepat dengan cepat dengan kalkulator gegelung geganti percuma ini. Semuanya berjalan secara setempat dalam penyemak imbas anda untuk privasi maksimum.
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