{"version":"1.0","provider_name":"SPLat Controls","provider_url":"https:\/\/webprojects.cloud\/wordpress\/splatco","author_name":"splatco","author_url":"https:\/\/webprojects.cloud\/wordpress\/splatco\/author\/splatco\/","title":"Unusual Construction - SPLat Controls","type":"rich","width":600,"height":338,"html":"<blockquote class=\"wp-embedded-content\" data-secret=\"16LY71CzOZ\"><a href=\"https:\/\/webprojects.cloud\/wordpress\/splatco\/product\/unusual-construction\/\">Unusual Construction<\/a><\/blockquote><iframe sandbox=\"allow-scripts\" security=\"restricted\" src=\"https:\/\/webprojects.cloud\/wordpress\/splatco\/product\/unusual-construction\/embed\/#?secret=16LY71CzOZ\" width=\"600\" height=\"338\" title=\"&#8220;Unusual Construction&#8221; &#8212; SPLat Controls\" data-secret=\"16LY71CzOZ\" frameborder=\"0\" marginwidth=\"0\" marginheight=\"0\" scrolling=\"no\" class=\"wp-embedded-content\"><\/iframe><script>\n\/*! This file is auto-generated *\/\n!function(d,l){\"use strict\";l.querySelector&&d.addEventListener&&\"undefined\"!=typeof URL&&(d.wp=d.wp||{},d.wp.receiveEmbedMessage||(d.wp.receiveEmbedMessage=function(e){var t=e.data;if((t||t.secret||t.message||t.value)&&!\/[^a-zA-Z0-9]\/.test(t.secret)){for(var s,r,n,a=l.querySelectorAll('iframe[data-secret=\"'+t.secret+'\"]'),o=l.querySelectorAll('blockquote[data-secret=\"'+t.secret+'\"]'),c=new RegExp(\"^https?:$\",\"i\"),i=0;i<o.length;i++)o[i].style.display=\"none\";for(i=0;i<a.length;i++)s=a[i],e.source===s.contentWindow&&(s.removeAttribute(\"style\"),\"height\"===t.message?(1e3<(r=parseInt(t.value,10))?r=1e3:~~r<200&&(r=200),s.height=r):\"link\"===t.message&&(r=new URL(s.getAttribute(\"src\")),n=new URL(t.value),c.test(n.protocol))&&n.host===r.host&&l.activeElement===s&&(d.top.location.href=t.value))}},d.addEventListener(\"message\",d.wp.receiveEmbedMessage,!1),l.addEventListener(\"DOMContentLoaded\",function(){for(var e,t,s=l.querySelectorAll(\"iframe.wp-embedded-content\"),r=0;r<s.length;r++)(t=(e=s[r]).getAttribute(\"data-secret\"))||(t=Math.random().toString(36).substring(2,12),e.src+=\"#?secret=\"+t,e.setAttribute(\"data-secret\",t)),e.contentWindow.postMessage({message:\"ready\",secret:t},\"*\")},!1)))}(window,document);\n<\/script>\n","thumbnail_url":"https:\/\/webprojects.cloud\/wordpress\/splatco\/wp-content\/uploads\/2025\/05\/Unusual-Construction-.jpg","thumbnail_width":223,"thumbnail_height":304,"description":"The picture on the left shows the BNC style probe connector. You will notice that the attached component leads have their connections off the printed circuit board. This is not untidy engineering on our part, it is necessary to provide the ultra high amplifier input resistance required for accurate pH measurement.  Glass pH probes (by the way, we don't supply probes) have an output resistance of up to 800 MegaOhms. The amplifier must have an input resistance orders of magnitude higher than that to preserve accuracy. The amplifier chip we use in the SX10507 is a National Semiconductors LPC661IM premium device. It has a worst case input current of 4pA, equivalent to an error of about 0.05 pH units.  The fibre glass of the printed circuit board is a good insulator, but not\u00a0that\u00a0good in relation to the ultra-high impedance levels in this situation. Air is a much better insulator, so that's what we use! Hence the \"air wiring\" of the input circuit. You can also see that we have used a high quality, ultra-low leakage polystyrene (aka expensive) capacitor for the input noise filtering. pH measurement primer (very, very simplified) A pH probe consists of glass bulbs filled with magic potions. When submerged in a liquid they generate a \u00b1 voltage of about 59mV per pH unit, with 0mV at pH7. The voltage generated in a given liquid is proportional to absolute temperature, and is governed by fundamental physics. In theory the actual pH changes with temperature, but In practice the reading is usually adjusted back to what it would be at 20\u00b0C. Hence a practical measuring system will include temperature compensation, and you can usually buy probes with an integral temperature sensor (typically a Pt1000)  Because the electrodes are glass they have a very, very high resistance. This means that the measuring circuit must have an ultra-high input resistance so as not to upset the accuracy.  The SX10507 has an ultra-ultra high input resistance and temperature measuring circuitry.  There's an excellent, more detailed\u00a0description of pH probes here."}