B503 50kΩ Linear Potentiometer Marking Meaning – Decoding 216c Factory Code

User question

What do potentiometer values B503 216c mean?

Artificial Intelligence Response

Direct answer to the question

• B503 ≡ 50 kΩ linear-taper potentiometer
  • “B” → linear taper (Europe/Asia coding)
  • “503” → 50 × 10³ Ω = 50 000 Ω
• 216c ≡ manufacturer trace code (date, lot, production line, or plant). It has no influence on electrical behaviour.

Detailed problem analysis

1. 3-digit resistance code
   • First two digits = significant figures (“50”)
   • Third digit = decimal multiplier (10³) → 50 kΩ

2. Taper / law coding
   • IEC/JIS coding: A = log/audio, B = linear, C = reverse-log.
   • ANSI/US sometimes swaps A/B, but the presence of “503” in 3-digit form almost always places the part in the IEC family, so “B” can be safely read as linear.

3. Secondary string “216c”
   • Potentiometer makers (Bourns, Alpha, Vishay, Piher, etc.) add 3- to 5-character fields for:
   – Year/week (21 = week 21, 6 = year 2016/2006, etc.)
   – Internal factory code (“c”), reel position, or inspection lot.
   • Decoding requires the manufacturer’s proprietary table; it is not part of any public standard.

4. Electrical tolerance & power
   • Unless explicitly printed elsewhere, general-purpose carbon/composite pots are ±20 % and ≤0.25 W at 70 °C.
   • Metal-film or cermet versions may be tighter (±10 … ±5 %).

Current information and trends

• Modern SMD/rotary hybrid pots and digital-resistance ICs are gradually replacing purely mechanical parts in new designs, but 3-digit + taper lettering remains the dominant marking convention for through-hole and panel pots.
• Some suppliers (e.g., Bourns PTF & PTL series) now laser-mark complete part numbers, but short codes like B503 persist on ultra-small or cost-sensitive models.
• Regulators and manufacturers are converging on RoHS/REACH compliant materials; no code change is visible on the device—check datasheet revision.

Supporting explanations and details

• Why linear vs. logarithmic?
  In an audio fader the ear’s ~log response needs a log pot (“A”). For bias, offset, gain-set, or brightness controls, linear (“B”) yields intuitive adjustment.
• Example measurement: Connect an ohmmeter across the two outer tags → ≈50 kΩ. Measure from one end to the wiper at 25 % rotation → ≈12.5 kΩ for linear, ≪5 kΩ for audio taper.

Ethical and legal aspects

• Lead-free legislation (RoHS) may affect replacement sourcing; always verify Pb-free status if equipment is exported to regions enforcing Directive 2011/65/EU.
• Counterfeit pots exist; inconsistent secondary codes, wrong taper curve, or odd shaft plating are common red flags.

Practical guidelines

1. Replacement checklist
   • Electrical: 50 kΩ, linear law, same or higher power rating.
   • Mechanical: shaft length/shape, bushing thread, pin spacing, detent?
2. Verification before installation
   • Measure total R and mid-span R to confirm taper.
   • If critical, plot R vs. angle (10 ° steps) and overlay the nominal linear curve (±20 %).
3. Mounting & ESD
   • Solder quickly <3 s per pin; prolonged heating drifts the resistive track.
   • Use anti-static precautions on conductive-plastic or cermet tracks.

Possible disclaimers or additional notes

• “B” = linear in IEC/JIS; US vendors occasionally label linear as “A”. If you are reverse-engineering US audio gear, double-check the datasheet.
• Without the manufacturer’s code book, “216c” cannot be resolved further.

Suggestions for further research

• Download the datasheet of likely vendors (e.g., Alpha RV24, Bourns PTD90, Vishay P11) and compare code formats.
• Explore digital potentiometers (e.g., Microchip MCP41xxx) when long-term repeatability or remote control is required.
• Investigate ISO 9001 traceability requirements if you are building safety-critical hardware.

Brief summary

“B503” unambiguously specifies a 50 kΩ linear-taper potentiometer; “216c” is merely the factory/date/lot identifier, having no effect on the part’s resistance or taper. For practical purposes, match 50 kΩ and linear law; ignore the secondary string unless traceability into the manufacturing chain is required.

Disclaimer: The responses provided by artificial intelligence (language model) may be inaccurate and misleading. Elektroda is not responsible for the accuracy, reliability, or completeness of the presented information. All responses should be verified by the user.