Temperature Sensing & Control · NTC, RTD & Thermocouple Sensors
Type K and Type J Thermocouples
Covering temperatures to 400 °C, rated for 5-24 V, built to IEC 60584 / IEC 60730 / RoHS. The capability table below states what the part is bounded by.
Type K and Type J Thermocouples are covering temperatures to 400 °C, rated for 5-24 V. It does not limit its own temperature: a thermostat, a thermal cutoff or a control loop with an independent over-temperature channel belongs in the design.
Continuous temperature
to 400 °C
Supply voltage
5-24 V
Maximum one-piece size
Component
Built and tested to
IEC 60584 / IEC 60730 / RoHS
These are the process limits for this construction, not the rating of a finished part. The ratings of your heater come from the drawing it is built to, and the watt density it can carry depends on what it is bonded to.
Outline & Specification Builder
Set the outline, the size, the voltage and the power you have in mind. The drawing
redraws to match, and the panel works out the heated area, the watt density and the current — then checks
that watt density against what this construction survives in free air and bonded to a heat sink. Those two
limits are different by several times, and it is the difference that decides whether a heater lasts.
Fills in the form below; attach your outline drawing or DXF there.
Request a Quotation for Type K and Type J Thermocouples
The form below follows the current technical drawing configuration. Change the drawing values above and the request details update automatically.
Every row below is a starting point for the customizer above — pick any size and the drawing will redraw to that row.
Parameter
Specification
Limit / note
Type K
Nickel-chromium / nickel-alumel, -200 u00b0C to +1200 u00b0C
The general purpose thermocouple
Type J
Iron / constantan, 0 u00b0C to +750 u00b0C
Higher output than K, but the iron leg corrodes in moist air
Standard
IEC 60584 class 1 or class 2
Class 1 is u00b11.5 u00b0C or u00b10.004|t| for type K
Junction
Grounded, ungrounded or exposed
Ungrounded avoids earth loops; exposed is fastest and least protected
Response time
Under 1 second exposed, 2 to 10 seconds sheathed
Cold junction
Compensation required at the instrument
A thermocouple measures a difference, not a temperature u2014 this is where most errors come from
Extension cable
Matching type, correct polarity
Copper extension wire silently destroys the measurement
Sheath
304 or 316 stainless, 1 mm to 6 mm diameter
Type K and Type J Thermocouples are temperature sensing & control. There is no catalogue size and no stocked part number here — the drawing decides the outline and the wattage. What this page gives you instead is everything that constrains the drawing: watt density, temperature, thickness, tolerance, voltage and the certifications the construction is built to.
What Are Type K and Type J Thermocouples?
Type K and Type J Thermocouples are temperature sensing & control. They are specified by rating together with the outline drawing, the wattage or the temperature to be held, and what the heater is bonded to — that last one decides the permissible watt density and is the question a quotation cannot skip. The construction is built and tested to IEC 60584 / IEC 60730 / RoHS.
Construction & Insulation System
These are the components that make a heated product safe and accurate, and they are not interchangeable with each other. A bimetal thermostat or a one-shot thermal cutoff protects; a thermistor, RTD or thermocouple measures; a controller closes the loop. Using one component for two of those jobs leaves the product with no protection in exactly the case protection exists for — the loop failing on.
Typical Applications
The protection and the measurement that every heated product needs: a thermostat or thermal cutoff in series with the element, a thermistor, RTD or thermocouple reading the surface that matters, and a controller closing the loop around them.
Inside the plant
Manufactured in our own plant
This heater is laid out, wound or etched, laminated, cut, tested and imaged in-house. The stages below are where its resistance tolerance, its temperature uniformity and its insulation integrity are actually decided.
01
Circuit design & layout
The customer outline comes in as a drawing or a DXF, and the element is laid out inside it: conductor gauge from the voltage, path length from the resistance, pitch from the watt density wanted at each part of the surface. Where the load needs more heat at the edges than in the middle, that is decided here, in the geometry, not later with more power.
Calculated resistance and watt density checked against the construction limits before any tooling is cut.
02
Element preparation
Wire-wound elements are wound on a glass carrier at the calculated pitch; etched-foil circuits are photo-imaged and etched from Inconel or copper foil to a trace width held within 0.05 mm. That tolerance is what makes the resistance repeatable from lot to lot, which is what makes the temperature repeatable.
Trace width and element resistance measured before lamination — a circuit out of tolerance is scrapped here, not after it is sealed inside the part.
03
Lamination & vulcanising
The element and its sensor are laid between the insulation and pressed under heat: silicone is vulcanised, polyimide and PET are laminated with a high temperature adhesive, epoxy plates are potted under vacuum so no voids are left anywhere in the heat path. A void is not a cosmetic defect — it is a place the heat cannot leave from, and it becomes the hot spot that ends the part.
Press temperature, pressure and dwell recorded per lot; potted plates checked for voids.
04
Die cutting & leads
The outline is die cut with radiused corners — a die does not cut an inside corner, and a sharp corner in a film is where a tear starts. Leads are crimped or soldered and strain relieved at the exit, and connectors are fitted to the harness drawing so the assembly line never has to solder.
Outline to ±0.5 mm on film, ±1.5 mm on silicone; lead pull-out tested per lot.
Third-party video, selected automatically for this topic. It is not produced by Heating Film and is not a specification source — use the tables on this page for dimensional data.
Frequently Asked Questions
How hot can Type K and Type J Thermocouples run?
400 °C continuously. That limit belongs to the insulation system — Aramid Paper (Nomex type) — not to the element, which would tolerate a good deal more. It is a hard ceiling: above it the insulation degrades, and no derating scheme buys headroom. Past 400 °C the construction has to change rather than be pushed.
How are Type K and Type J Thermocouples fitted?
They are clamped, bonded or potted against the surface whose temperature it has to read — a sensor mounted in the air near a heater reads the air, and the loop then controls the wrong thing.
What voltages are Type K and Type J Thermocouples available in?
5 V DC, 12 V DC and 24 V DC. The element is wound for the voltage ordered — it is not a switchable range, and running a heater at a voltage other than the one it was wound for changes its power by the square of the ratio.
How do I get a quotation?
Set the outline, size, voltage and power in the builder on this page and send that configuration through, or attach a drawing. The quotation needs six things: the outline, the supply voltage, the power or the temperature you need to hold, what the heater is bonded to, the ambient it works in, and the quantity. With those, a quotation comes back within one business day.
Need a heater quoted?Message our engineers on WhatsApp — send an outline drawing and the supply voltage and get pricing back fast.Start WhatsApp Chat →
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