{"id":3281,"date":"2025-04-17T11:52:36","date_gmt":"2025-04-17T11:52:36","guid":{"rendered":"https:\/\/webprojects.cloud\/wordpress\/splatco\/?post_type=spl_knowledgebase&p=3281"},"modified":"2025-06-10T07:34:48","modified_gmt":"2025-06-10T07:34:48","slug":"scel-tm08-thermistor-temperature-circuit","status":"publish","type":"spl_knowledgebase","link":"https:\/\/webprojects.cloud\/wordpress\/splatco\/knowledgebase\/custom-splat\/splat-circuit-element-library\/scel-tm08-thermistor-temperature-circuit\/","title":{"rendered":"SCEL: TM08 thermistor temperature circuit"},"content":{"rendered":"\n
\"\"<\/figure>\n\n\n\n

The SCEL:TM08 circuit will provide modest accuracy and resolution temperature measurements at very low cost. The underlying premise of this design is that very many control applications require temperature measurement over a restricted temperature range. For example, if you are making a washing machine you may be quite happy to measure temperatures between 60\u00b0C and 100\u00b0C, with a nominal target temperature of 85\u00b0C.<\/p>\n\n\n\n

Normally you would source your own NTC thermistors. Very likely you will need some special encapsulation or mounting. Naturally, we’ll attempt to suggest suitable thermistors, and we do know of some already packaged industrial type units.

The circuit used to interface the thermistor is quite simple (hence the low cost). We will scale this circuit for your specific needs during the definition phase of your design. Because thermistors are non-linear, you may need to linearise the raw readings to get \u00b0C or \u00b0F. This is quite a simple matter with SPLat, thanks to the built in floating point arithmetic. There is a tutorial<\/a> in the SPLat Knowledge Base, and a supporting spreadsheet that generates the linearising polynomial.<\/p>\n\n\n\n

This circuit, in various versions, has been used on several SPLat boards, including MMi99<\/a>, SL99<\/a>, SPice10200<\/a> and AJ18.<\/p>\n\n\n\n

The following characteristic data is for two typical applications. When negotiating an implementation of this, or any other circuit element in your custom SPLat controller, you must identify the parameters that are most critical.<\/p>\n\n\n\n

 <\/td>Appn. 1<\/td>Appn. 2<\/td><\/tr>
Description<\/td>Food storage & chilling<\/td>Industrial parts cleaner<\/td><\/tr>
Temperature range<\/td>-3\u00b0C – +40\u00b0C<\/td>10\u00b0C – 110\u00b0C<\/td><\/tr>
Critical temp range<\/td>0\u00b0C – 6\u00b0C<\/td>75\u00b0C – 90\u00b0C<\/td><\/tr>
Accuracy<\/td>0.2\u00b0C @ calibration point<\/td>2\u00b0C<\/td><\/tr>
Resolution, critical range<\/td>0.13\u00b0C<\/td>0.5\u00b0C<\/td><\/tr>
Resolution, full range<\/td>0.5\u00b0C<\/td>1.34\u00b0C<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

Application 1 was very critical around the optimum storage temperature. In such cases it may be necessary to calibrate the system close to the critical temperature.<\/p>\n\n\n\n

Application 2 is not at all critical, so no calibration was performed. The basic accuracy then achieved is a function of the grade of thermistor and of circuit errors.<\/p>\n\n\n\n

Resolution (the smallest detectable change in temperature) is a function of the analog to digital conversion resolution. For low cost applications we provide 8 bit conversion, and the above figures are based on that. By adjusting circuit parameters we can optimize the circuit to get best resolution around the critical temperature.<\/p>\n\n\n\n

Thermistors provide the lowest cost temperature measurement, both because the thermistor devices are very cheap and because the circuitry needed to support them is very simple. Surprisingly, thermistors also provide very good accuracy relative to sensor price. Thermistors are available for around $5 that have <0.1\u00b0C inherent accuracy, and for less than $1 more ordinary thermistors still have inherent accuracies of 1\u00b0C or so. This compares very favourably with semiconductor sensors that often have accuracies of 2\u00b0C or worse.<\/p>\n\n\n\n

“Ordinary” thermistors have working temperature ranges from -50\u00b0C to +180\u00b0C. One company makes units that go up to 700\u00b0C.<\/p>\n","protected":false},"excerpt":{"rendered":"

The SCEL:TM08 circuit will provide modest accuracy and resolution temperature measurements at very low cost. The underlying premise of this design is that very many…<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":3260,"menu_order":3,"template":"","class_list":["post-3281","spl_knowledgebase","type-spl_knowledgebase","status-publish","hentry"],"acf":[],"yoast_head":"\nSCEL: TM08 thermistor temperature circuit - SPLat Controls<\/title>\n<meta name=\"robots\" content=\"noindex, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"SCEL: TM08 thermistor temperature circuit - SPLat Controls\" \/>\n<meta property=\"og:description\" content=\"The SCEL:TM08 circuit will provide modest accuracy and resolution temperature measurements at very low cost. The underlying premise of this design is that very many...\" \/>\n<meta property=\"og:url\" content=\"https:\/\/webprojects.cloud\/wordpress\/splatco\/knowledgebase\/custom-splat\/splat-circuit-element-library\/scel-tm08-thermistor-temperature-circuit\/\" \/>\n<meta property=\"og:site_name\" content=\"SPLat Controls\" \/>\n<meta property=\"article:modified_time\" content=\"2025-06-10T07:34:48+00:00\" \/>\n<meta property=\"og:image\" content=\"https:\/\/webprojects.cloud\/wordpress\/splatco\/wp-content\/uploads\/2025\/04\/TM08-thermistor.jpg\" \/>\n\t<meta property=\"og:image:width\" content=\"200\" \/>\n\t<meta property=\"og:image:height\" content=\"148\" \/>\n\t<meta property=\"og:image:type\" content=\"image\/jpeg\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"Est. reading time\" \/>\n\t<meta name=\"twitter:data1\" content=\"3 minutes\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\/\/schema.org\",\"@graph\":[{\"@type\":\"WebPage\",\"@id\":\"https:\/\/webprojects.cloud\/wordpress\/splatco\/knowledgebase\/custom-splat\/splat-circuit-element-library\/scel-tm08-thermistor-temperature-circuit\/\",\"url\":\"https:\/\/webprojects.cloud\/wordpress\/splatco\/knowledgebase\/custom-splat\/splat-circuit-element-library\/scel-tm08-thermistor-temperature-circuit\/\",\"name\":\"SCEL: TM08 thermistor temperature circuit - SPLat Controls\",\"isPartOf\":{\"@id\":\"https:\/\/webprojects.cloud\/wordpress\/splatco\/#website\"},\"primaryImageOfPage\":{\"@id\":\"https:\/\/webprojects.cloud\/wordpress\/splatco\/knowledgebase\/custom-splat\/splat-circuit-element-library\/scel-tm08-thermistor-temperature-circuit\/#primaryimage\"},\"image\":{\"@id\":\"https:\/\/webprojects.cloud\/wordpress\/splatco\/knowledgebase\/custom-splat\/splat-circuit-element-library\/scel-tm08-thermistor-temperature-circuit\/#primaryimage\"},\"thumbnailUrl\":\"https:\/\/webprojects.cloud\/wordpress\/splatco\/wp-content\/uploads\/2025\/04\/TM08-thermistor.jpg\",\"datePublished\":\"2025-04-17T11:52:36+00:00\",\"dateModified\":\"2025-06-10T07:34:48+00:00\",\"breadcrumb\":{\"@id\":\"https:\/\/webprojects.cloud\/wordpress\/splatco\/knowledgebase\/custom-splat\/splat-circuit-element-library\/scel-tm08-thermistor-temperature-circuit\/#breadcrumb\"},\"inLanguage\":\"en-US\",\"potentialAction\":[{\"@type\":\"ReadAction\",\"target\":[\"https:\/\/webprojects.cloud\/wordpress\/splatco\/knowledgebase\/custom-splat\/splat-circuit-element-library\/scel-tm08-thermistor-temperature-circuit\/\"]}]},{\"@type\":\"ImageObject\",\"inLanguage\":\"en-US\",\"@id\":\"https:\/\/webprojects.cloud\/wordpress\/splatco\/knowledgebase\/custom-splat\/splat-circuit-element-library\/scel-tm08-thermistor-temperature-circuit\/#primaryimage\",\"url\":\"https:\/\/webprojects.cloud\/wordpress\/splatco\/wp-content\/uploads\/2025\/04\/TM08-thermistor.jpg\",\"contentUrl\":\"https:\/\/webprojects.cloud\/wordpress\/splatco\/wp-content\/uploads\/2025\/04\/TM08-thermistor.jpg\",\"width\":200,\"height\":148},{\"@type\":\"BreadcrumbList\",\"@id\":\"https:\/\/webprojects.cloud\/wordpress\/splatco\/knowledgebase\/custom-splat\/splat-circuit-element-library\/scel-tm08-thermistor-temperature-circuit\/#breadcrumb\",\"itemListElement\":[{\"@type\":\"ListItem\",\"position\":1,\"name\":\"Home\",\"item\":\"https:\/\/webprojects.cloud\/wordpress\/splatco\/\"},{\"@type\":\"ListItem\",\"position\":2,\"name\":\"Custom SPLat\",\"item\":\"https:\/\/webprojects.cloud\/wordpress\/splatco\/knowledgebase\/custom-splat\/\"},{\"@type\":\"ListItem\",\"position\":3,\"name\":\"SPLat Circuit Element Library\",\"item\":\"https:\/\/webprojects.cloud\/wordpress\/splatco\/knowledgebase\/custom-splat\/splat-circuit-element-library\/\"},{\"@type\":\"ListItem\",\"position\":4,\"name\":\"SCEL: TM08 thermistor temperature circuit\"}]},{\"@type\":\"WebSite\",\"@id\":\"https:\/\/webprojects.cloud\/wordpress\/splatco\/#website\",\"url\":\"https:\/\/webprojects.cloud\/wordpress\/splatco\/\",\"name\":\"SPLat Controls\",\"description\":\"OEM Embedded Machine Controllers\",\"publisher\":{\"@id\":\"https:\/\/webprojects.cloud\/wordpress\/splatco\/#organization\"},\"potentialAction\":[{\"@type\":\"SearchAction\",\"target\":{\"@type\":\"EntryPoint\",\"urlTemplate\":\"https:\/\/webprojects.cloud\/wordpress\/splatco\/?s={search_term_string}\"},\"query-input\":{\"@type\":\"PropertyValueSpecification\",\"valueRequired\":true,\"valueName\":\"search_term_string\"}}],\"inLanguage\":\"en-US\"},{\"@type\":\"Organization\",\"@id\":\"https:\/\/webprojects.cloud\/wordpress\/splatco\/#organization\",\"name\":\"SPLat Controls\",\"url\":\"https:\/\/webprojects.cloud\/wordpress\/splatco\/\",\"logo\":{\"@type\":\"ImageObject\",\"inLanguage\":\"en-US\",\"@id\":\"https:\/\/webprojects.cloud\/wordpress\/splatco\/#\/schema\/logo\/image\/\",\"url\":\"https:\/\/webprojects.cloud\/wordpress\/splatco\/wp-content\/uploads\/2024\/10\/logo.svg\",\"contentUrl\":\"https:\/\/webprojects.cloud\/wordpress\/splatco\/wp-content\/uploads\/2024\/10\/logo.svg\",\"caption\":\"SPLat Controls\"},\"image\":{\"@id\":\"https:\/\/webprojects.cloud\/wordpress\/splatco\/#\/schema\/logo\/image\/\"}}]}<\/script>\n<!-- \/ Yoast SEO plugin. -->","yoast_head_json":{"title":"SCEL: TM08 thermistor temperature circuit - SPLat Controls","robots":{"index":"noindex","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"og_locale":"en_US","og_type":"article","og_title":"SCEL: TM08 thermistor temperature circuit - SPLat Controls","og_description":"The SCEL:TM08 circuit will provide modest accuracy and resolution temperature measurements at very low cost. The underlying premise of this design is that very many...","og_url":"https:\/\/webprojects.cloud\/wordpress\/splatco\/knowledgebase\/custom-splat\/splat-circuit-element-library\/scel-tm08-thermistor-temperature-circuit\/","og_site_name":"SPLat Controls","article_modified_time":"2025-06-10T07:34:48+00:00","og_image":[{"width":200,"height":148,"url":"https:\/\/webprojects.cloud\/wordpress\/splatco\/wp-content\/uploads\/2025\/04\/TM08-thermistor.jpg","type":"image\/jpeg"}],"twitter_card":"summary_large_image","twitter_misc":{"Est. reading time":"3 minutes"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"WebPage","@id":"https:\/\/webprojects.cloud\/wordpress\/splatco\/knowledgebase\/custom-splat\/splat-circuit-element-library\/scel-tm08-thermistor-temperature-circuit\/","url":"https:\/\/webprojects.cloud\/wordpress\/splatco\/knowledgebase\/custom-splat\/splat-circuit-element-library\/scel-tm08-thermistor-temperature-circuit\/","name":"SCEL: TM08 thermistor temperature circuit - SPLat Controls","isPartOf":{"@id":"https:\/\/webprojects.cloud\/wordpress\/splatco\/#website"},"primaryImageOfPage":{"@id":"https:\/\/webprojects.cloud\/wordpress\/splatco\/knowledgebase\/custom-splat\/splat-circuit-element-library\/scel-tm08-thermistor-temperature-circuit\/#primaryimage"},"image":{"@id":"https:\/\/webprojects.cloud\/wordpress\/splatco\/knowledgebase\/custom-splat\/splat-circuit-element-library\/scel-tm08-thermistor-temperature-circuit\/#primaryimage"},"thumbnailUrl":"https:\/\/webprojects.cloud\/wordpress\/splatco\/wp-content\/uploads\/2025\/04\/TM08-thermistor.jpg","datePublished":"2025-04-17T11:52:36+00:00","dateModified":"2025-06-10T07:34:48+00:00","breadcrumb":{"@id":"https:\/\/webprojects.cloud\/wordpress\/splatco\/knowledgebase\/custom-splat\/splat-circuit-element-library\/scel-tm08-thermistor-temperature-circuit\/#breadcrumb"},"inLanguage":"en-US","potentialAction":[{"@type":"ReadAction","target":["https:\/\/webprojects.cloud\/wordpress\/splatco\/knowledgebase\/custom-splat\/splat-circuit-element-library\/scel-tm08-thermistor-temperature-circuit\/"]}]},{"@type":"ImageObject","inLanguage":"en-US","@id":"https:\/\/webprojects.cloud\/wordpress\/splatco\/knowledgebase\/custom-splat\/splat-circuit-element-library\/scel-tm08-thermistor-temperature-circuit\/#primaryimage","url":"https:\/\/webprojects.cloud\/wordpress\/splatco\/wp-content\/uploads\/2025\/04\/TM08-thermistor.jpg","contentUrl":"https:\/\/webprojects.cloud\/wordpress\/splatco\/wp-content\/uploads\/2025\/04\/TM08-thermistor.jpg","width":200,"height":148},{"@type":"BreadcrumbList","@id":"https:\/\/webprojects.cloud\/wordpress\/splatco\/knowledgebase\/custom-splat\/splat-circuit-element-library\/scel-tm08-thermistor-temperature-circuit\/#breadcrumb","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https:\/\/webprojects.cloud\/wordpress\/splatco\/"},{"@type":"ListItem","position":2,"name":"Custom SPLat","item":"https:\/\/webprojects.cloud\/wordpress\/splatco\/knowledgebase\/custom-splat\/"},{"@type":"ListItem","position":3,"name":"SPLat Circuit Element Library","item":"https:\/\/webprojects.cloud\/wordpress\/splatco\/knowledgebase\/custom-splat\/splat-circuit-element-library\/"},{"@type":"ListItem","position":4,"name":"SCEL: TM08 thermistor temperature circuit"}]},{"@type":"WebSite","@id":"https:\/\/webprojects.cloud\/wordpress\/splatco\/#website","url":"https:\/\/webprojects.cloud\/wordpress\/splatco\/","name":"SPLat Controls","description":"OEM Embedded Machine Controllers","publisher":{"@id":"https:\/\/webprojects.cloud\/wordpress\/splatco\/#organization"},"potentialAction":[{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https:\/\/webprojects.cloud\/wordpress\/splatco\/?s={search_term_string}"},"query-input":{"@type":"PropertyValueSpecification","valueRequired":true,"valueName":"search_term_string"}}],"inLanguage":"en-US"},{"@type":"Organization","@id":"https:\/\/webprojects.cloud\/wordpress\/splatco\/#organization","name":"SPLat Controls","url":"https:\/\/webprojects.cloud\/wordpress\/splatco\/","logo":{"@type":"ImageObject","inLanguage":"en-US","@id":"https:\/\/webprojects.cloud\/wordpress\/splatco\/#\/schema\/logo\/image\/","url":"https:\/\/webprojects.cloud\/wordpress\/splatco\/wp-content\/uploads\/2024\/10\/logo.svg","contentUrl":"https:\/\/webprojects.cloud\/wordpress\/splatco\/wp-content\/uploads\/2024\/10\/logo.svg","caption":"SPLat Controls"},"image":{"@id":"https:\/\/webprojects.cloud\/wordpress\/splatco\/#\/schema\/logo\/image\/"}}]}},"_links":{"self":[{"href":"https:\/\/webprojects.cloud\/wordpress\/splatco\/wp-json\/wp\/v2\/spl_knowledgebase\/3281","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/webprojects.cloud\/wordpress\/splatco\/wp-json\/wp\/v2\/spl_knowledgebase"}],"about":[{"href":"https:\/\/webprojects.cloud\/wordpress\/splatco\/wp-json\/wp\/v2\/types\/spl_knowledgebase"}],"author":[{"embeddable":true,"href":"https:\/\/webprojects.cloud\/wordpress\/splatco\/wp-json\/wp\/v2\/users\/1"}],"up":[{"embeddable":true,"href":"https:\/\/webprojects.cloud\/wordpress\/splatco\/wp-json\/wp\/v2\/spl_knowledgebase\/3260"}],"wp:attachment":[{"href":"https:\/\/webprojects.cloud\/wordpress\/splatco\/wp-json\/wp\/v2\/media?parent=3281"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}