Resistor 0.25W 3.9 ohm (10 pcs)

The Resistor 0.25W 3.9 ohm is a through-hole fixed resistor with a very low resistance of 3.9 Ω and a power rating of 0.25 W (1/4 W), sold in a pack of 10. Values this low are used to measure or limit current with only a small voltage drop, for example as current-sense resistors and small series resistors in power and audio circuits.

Resistor 0.25W 3.9 ohm Specifications

• Resistance: 3.9 Ω (also written 3R9)
• Power rating: 0.25 W (1/4 W)
• Maximum current: about 250 mA at the full 0.25 W rating
• Colour code: orange, white, gold (4-band) or orange, white, black, silver (5-band), plus a tolerance band
• Type: fixed resistor, axial leads, through-hole
• Pack size: 10 pieces

Resistor 0.25W 3.9 ohm Applications

• Current-sense resistors: 100 mA through 3.9 Ω gives a 0.39 V drop to measure
• Small series resistors that limit inrush and fault current
• Emitter degeneration resistors in transistor stages
• Series resistors in low-voltage LED and motor test circuits
• Electronics education and repair work

What's in the Box

• 10 × 3.9 Ω 0.25 W resistors

Tip: At low resistance the current rises quickly, so always calculate the power with P = I² × R. Keep the current below about 250 mA, and choose a higher-wattage resistor for anything more.

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