Name: Isotech Semi-Standard PRTs | High-Stability Reference PRTs
Price: 1 USD
Availability: InStock

Overview

Isotech Semi-Standard PRTs provide the accuracy, stability, and robustness needed for day-to-day reference work in dry-blocks and calibration baths. The range covers general-purpose, low-temperature, high-temperature and angled 90° variants to clear bath rims and terminal heads. Typical stability for a correctly used semi-standard is 0.01 °C/year, with UKAS calibration available.

Model Matrix

Straight probes

935-14-112 (3 mm × 225 mm, –50…250 °C): general purpose / TTI-10.
935-14-61 (4 mm × 300 mm, –50…250 °C): fast response, low stem conduction.
935-14-13 / -113 / -16 / -116 (6 mm × 350–450 mm, ranges –196…250 °C to –100…450 °C): low-temp & general-purpose working standards.
935-14-72 (6 mm × 375 mm, –50…670 °C): compact high-range, fits Jupiter/Gemini carry case.
935-14-98 (4 mm × 300 mm, –50…350 °C): low stem conduction.
935-14-95L / -95H (6 mm × 480 mm, –200…165 °C and –80…670 °C): working standards with long stem.

Angled probes (90° head)

935-14-82 (4 mm, –50…250 °C), Europa / Venus / Calisto portable calibrators.
935-14-85 (6 mm, –50…250 °C), Oceanus-6.
935-14-75 (6 mm, –50…250 °C) and 935-14-79 (6 mm, 0…660 °C): clearance over bath tops; options for Gemini & Jupiter.

Cables & handles: 2 m PTFE cable standard; selected models supplied with compact handle; see datasheet table for A/B/C dimensions.

Key Features & Specifications

Temperature ranges: –196…+670 °C (model dependent).
Construction: platinum element, 4-wire measurement, low stem conduction options.
Electrical (typical): R₀ = 100 Ω ±0.05 Ω, α = 0.003850 ± 0.000005, recommended current 1 mA, self-heating at 1 mA ~0.004 °C.
Standards: IEC 60751 (ITS-90 compatible).
Uncertainties (typical, mK at point of use): e.g., 10 mK at 0 °C for most straight models; see table for values at –196, –80, –50, 0, 50, 156, 232 °C etc.
Stability: ~0.01 °C/year (typical when correctly used).
Terminations: BW (bare wire), TTI (milliK / TTI-1…TTI-7 / TTI-b for TTI-22), DB connector for dry-block site indicator.
Calibration: UKAS certificates available for these systems.

Applications

Working standards with dry-blocks (Europa, Venus, Calisto, Gemini, Jupiter, Oceanus-6).
Laboratory calibration baths and uncertainty studies.
Field verification with portable calibrators (angled models give rim clearance).
High-stability references for TTI/milliK indicators.

What’s Included

Probe to ordered model, 2 m PTFE cable, termination as specified (BW/TTI/DB), basic QC data. UKAS certificate optional.

Options / How to Order

Select model (e.g., 935-14-72). 2) Choose termination: /BW, /TTI-b, or /DB. 3) State if UKAS calibration is required. Example: 935-14-13/BW.

FAQ

Q1: What’s the difference between “semi-standard” and “standard” PRTs?

Semi-standards are optimized for day-to-day working reference use: robust stems, low drift (~0.01 °C/year), and uncertainties ~10 mK at 0 °C—perfect for dry-blocks and baths.

Q2: Which probe suits my portable calibrator?

Use angled models (e.g., 935-14-75 / -79) for Europa/Venus/Calisto or Gemini/Jupiter to clear the top of the calibrator.

Q3: Can I get UKAS calibration?

Yes—UKAS calibration available for these systems for international traceability.

Q4: What terminations are available?

BW bare wire, TTI (milliK/TTI-22), or DB connector for dry-blocks with site indicator.

Q5: Electrical constants?

Typical R₀ = 100 Ω ± 0.05 Ω, α = 0.003850 ± 0.000005, 4-wire, 1 mA measurement current.

Call to Action

Seven Star LLC supplies genuine Isotech Semi-Standard PRTs with regional support, UKAS calibration options, and help selecting the right model/termination for your dry-block or bath. Send your calibrator model and required range—we’ll confirm the best probe, lead time, and pricing.