Product Overview
Econistor 8E16 Series 12.5 Ohm Ultra-Precision Axial Wirewound Resistor, 0.1% Tolerance, ±5 ppm/°C TCR
Condition
Unused NOS. Visually clean and pristine with no signs of use or damage. Blue text markings on the black epoxy body are clear and legible - photo observations confirm E31 markings and 12.5Ω 0.1% as stamped. Both axial leads are straight and undamaged. Sourced from an electronics distributor consolidating inventory.
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Product Overview
Econistor 8E16-12.5-D - a vintage ultra-precision wirewound resistor from the General Resistance / Prime Technology legacy line. Resistance value is 12.5 ohms with a 0.1% tolerance (tolerance code D in the General Resistance catalog system). The 8E16 series designation identifies the physical body size: 12.70 mm maximum length, axial lead package. Construction is precision wirewound - a specialized resistive alloy wire wound around a ceramic mandrel and encapsulated in a rugged moisture-resistant epoxy cylinder. Windings are balanced multiple-pi and non-inductively wound for low reactance. The result is a component engineered for long-term stability, minimal temperature drift, and essentially non-measurable noise - the characteristics that define a calibration-grade resistor.
Key Features
- Resistance: 12.5 ohms
- Tolerance: 0.1% (General Resistance code D)
- TCR: ±5 ppm/°C maximum over -55°C to +125°C; ±3 ppm/°C typical over 0°C to +85°C
- Power rating: 0.33W at +85°C
- Maximum continuous working voltage: up to 250V DC or peak
- Operating temperature range: -55°C to +160°C
- Stability: ±35 ppm per 10,000 hours at full load; ±25 ppm per 10,000 hours at no load
- Thermal EMF: less than 0.4 µV/°C typical, less than 1.5 µV/°C maximum
- Noise: essentially non-measurable
- Construction: non-inductively wound precision wirewound, ceramic mandrel, epoxy encapsulation
- Package: axial lead, 12.70 mm body length
- Series: 8E16 (General Resistance / Econistor); face stamp markings E31 and 12.5Ω 0.1% confirmed by photo
Applications
- Calibration technician integrating a stable reference into a bridge circuit to verify multimeter or instrument accuracy against a known 12.5-ohm standard
- Metrology engineer building a precision voltage divider where resistance drift over temperature and time would compound measurement error
- Vintage audio repair tech replacing a failed precision resistor in a high-fidelity attenuator where signal level accuracy and low noise matter more than cost
- Audiophile builder wiring a passive attenuator for a tube preamp or stepped volume control and specifying wirewound for minimum noise floor contribution
- Aerospace or industrial electronics tech maintaining a control loop or sensing circuit that must hold its calibration point across a wide operating temperature range
- Maker or experimenter building a precision Wheatstone bridge, RTD simulation circuit, or any analog measurement application where a stable low-value reference resistance is the keystone
Frequently Asked Questions
Is this the same part whether I search by 8E16-12.5-D or E31-12.5-0.1?
Yes. The official General Resistance catalog string is 8E16-12.5-D. The face stamp on the epoxy body reads E31 with 12.5Ω and 0.1% - both designations refer to the same component. If you spotted the markings on a board under magnification and typed what you saw, you have found the right listing.
What does the tolerance code D mean?
D is the General Resistance letter code for ±0.1% tolerance. On this part, the 0.1% is also printed directly on the body, so there is no ambiguity.
What is the power rating, and what happens if I exceed it?
The 8E16 series at 0.1% tolerance is rated 0.33W at +85°C ambient. Exceeding that rating does not necessarily destroy the resistor immediately, but it will drive the resistance value outside its specified tolerance window - which defeats the entire purpose of buying a precision part. Size your circuit so dissipation stays comfortably below 0.33W.
Does the non-inductive winding make this suitable for AC measurement circuits?
The balanced multiple-pi non-inductive winding design minimizes parasitic inductance, which is why this series is used in precision instrumentation and bridge circuits. For very high-frequency RF applications, any wirewound construction has residual parasitics that may be a factor. For audio frequencies and precision low-frequency AC measurement work, this construction is well suited.
What are the physical dimensions?
The 8E16 series has a body length of 12.70 mm maximum. Photo observations of this specific unit show the black epoxy body at approximately 7.5 to 8 mm, with axial leads spanning roughly 100 mm total. Verify your board layout against the 12.70 mm maximum body spec before ordering.
A 12.5-ohm reference point built to hold its value through temperature swings, decades of shelf storage, and the scrutiny of a calibration bench - whoever first specified this part knew exactly what they were asking for. Now it is ready for whatever circuit you have been waiting to finish.
