Resistor 0.5W 3.9 ohm (5 pcs)

The Resistor 0.5W 3.9 ohm is a low-ohm through-hole fixed resistor with a resistance of 3.9 Ω and a power rating of 0.5 W, sold in a pack of 5. It is mainly used where currents are a few hundred milliamps, for example as a current-sense resistor, a series resistor for power LEDs or a small load in test circuits.

Resistor 0.5W 3.9 ohm Specifications

• Resistance: 3.9 Ω
• Power rating: 0.5 W (1/2 W)
• Maximum current at 0.5 W: about 358 mA (P = I² × R)
• Series: standard E12 value
• Type: fixed resistor, axial leads, through-hole
• Fits: breadboards, perfboards and PCBs
• Pack size: 5 pieces

Resistor 0.5W 3.9 ohm Applications

• Current sensing with a multimeter, an Arduino analog input or an op-amp
• Series resistor for 1 W LEDs
• Emitter resistors in small transistor amplifier stages
• Replacement part in chargers, adapters and audio boards
• Electronics prototyping

What's in the Box

• 5 × 3.9 Ω 0.5 W resistors

Tip: Ohm's law makes current sensing easy: 0.39 V across this resistor means 100 mA. Keep the current under about 358 mA (P = I² × R = 0.5 W); for higher currents choose a 1 W or larger resistor.

Orders placed before 14:00 are ready for pickup the same day. Delivery across Lebanon usually takes 1–3 working days.