10pcs 51 ohms 5 band 1/4w

🔹 10PCS 51 Ohm (51Ω) Metal Film Resistor – 1/4 Watt, 5-Band

High-precision, low-noise metal film resistors with a 51 ohm value and 1% tolerance. Identified by a 5-band color code, these components are essential for precision current limiting, impedance matching, termination, and low-value feedback circuits where stable and accurate resistance is critical.

✅ Specifications:

• Resistance: 51 Ohms (51Ω)

• Tolerance: ±1% (Indicated by Brown 5th band)

• Power Rating: 1/4 Watt (0.25W)

• Type: Metal Film (Precision, Low Noise)

• Band Code: 5-Band

  • 1st Band: Green (5)

  • 2nd Band: Brown (1)

  • 3rd Band: Black (0)

  • 4th Band: Gold (Multiplier x 0.1)

  • 5th Band: Brown (±1%)

• Package: Axial Leads

• Lead Spacing: Standard ~10mm (0.4″)

• Temperature Coefficient: Typically ±50 to ±100 ppm/°C

• Operating Temperature: -55°C to +155°C

• Quantity: 10 pieces

⚙️ Key Features:

• High Precision: 1% tolerance ensures the actual resistance is tightly centered around 51Ω (range: 50.49Ω to 51.51Ω).

• Low Noise: Metal film construction generates significantly less inherent noise than carbon film, making them perfect for sensitive analog and audio circuits.

• Excellent Stability: Low temperature coefficient means resistance changes very little with temperature fluctuations.

• Clear 5-Band Coding: The extra band and gold 4th band (multiplier of 0.1) allow precise identification of this low value.

• Reliable & Durable: Robust construction for long-term stability.

📦 Typical Applications:

• Precision Current Limiting: For LEDs, laser diodes, or precision references requiring exact current control.

• Impedance Matching & Termination: For RF circuits, video lines, or high-speed digital signal lines (e.g., as a series termination resistor).

• Low-Value Feedback Networks: In op-amp circuits, particularly inverting amplifiers, for setting specific low gain values.

• Current Sensing Shunt: For low-current measurement applications (max measurable current ≈ 70mA for full-scale at 0.25W).

• Pull-Down Resistors: For specific digital interfaces or switch debouncing where a precise low-value pull-down is needed.

🔧 Usage & Calculations:

• Ohm’s Law (for Safe Operation):

  • Max Continuous Current: Imax=P/R=0.25/51≈0.070AImax​=P/R​=0.25/51​≈0.070A or 70mA.

  • Max Voltage Drop: Vmax=P×R=0.25×51≈3.57VVmax​=P×R​=0.25×51​≈3.57V.

• Power Dissipation: Due to the relatively low resistance, power dissipation can become significant. Always calculate P=I2RP=I2R. For example, at 50mA, P=(0.05)2∗51=0.1275WP=(0.05)2∗51=0.1275W, which is 51% of the rating.

• Current Sensing Example: To measure a 100mA current, the power would be 0.12∗51=0.51W0.12∗51=0.51W, which would exceed the rating and cause failure. Use a milliohm-range shunt for higher current sensing.

⚠️ Important Safety & Design Notes:

• Power Dissipation Limit: This is a primary constraint. Exceeding 0.25W will cause overheating and failure. For applications near the 70mA limit, use a higher wattage resistor (e.g., 1/2W or 1W).

• Heat Generation: Will become warm to hot when operating above ~50mA. Ensure adequate spacing and ventilation.

• Not for High-Current Shunts: Not suitable for measuring currents above ~70mA continuously. Use dedicated, high-power shunt resistors.

• Precision: The ±1% tolerance is excellent for matching and precise circuit design. For critical current sources, measure and select matched resistors.