{"id":1230,"date":"2012-10-15T06:57:02","date_gmt":"2012-10-15T06:57:02","guid":{"rendered":"http:\/\/localhost\/wordpress\/?page_id=1230"},"modified":"2012-10-16T15:34:40","modified_gmt":"2012-10-16T15:34:40","slug":"faq-instrumentation","status":"publish","type":"page","link":"https:\/\/www.noiseboard.com\/?page_id=1230","title":{"rendered":"[FAQ] Instrumentation"},"content":{"rendered":"<p><a name=\"top\"><\/a><\/p>\n<h2 style=\"background-color: #aac5e0;\">Questions<\/h2>\n<ul>\n<li><a href=\"#q17\">How do the units on the B&amp;K 2635 charge amplifier work<\/a><\/li>\n<\/ul>\n<h2 style=\"background-color: #aac5e0;\">Answers<\/h2>\n<p><a name=\"q17\"><\/a><\/p>\n<div><strong>How do the units on the B&amp;K 2635 charge amplifier work<\/strong>The knobs on the front of the B&amp;K 2635 charge amplifer are not intuitive. Here is how to calculate the effective calibration factor in units of V \/ Engineering Units,<code>Sp = ( A * 0.001 * B ) \/ C<\/code><\/p>\n<p>where<\/p>\n<ul>\n<li><code>A<\/code> is the sensitivity selected on the dial in mV \/ Unit Out<\/li>\n<li><code>B<\/code> is the exponent which is the multiplier between the actual sensitivity of the transducer and the sensitivity that was entered on the three dials on the top of the charge amplifier<\/li>\n<li><code>C<\/code> is the Unit out selected with the Acc &#8211; Vel &#8211; Disp knob.<\/li>\n<\/ul>\n<p>For example, if you have a transducer with a sensitivity of 67.2 pC \/ m\/s^2. You enter a sensitivity on the charge amplifier of 0.672 (with the switch on the left hand side in the up position indicating 0.1 &#8211; 1). The gain dial is set to 1000 mV \/ Unit Out. You are measuring acceleration and the units out are 1 m\/s^2 and high pass of 0.2Hz. Entering this data into the equation for <code>Sp<\/code> yields<\/p>\n<p><code>A = 1000<\/code> (gain setting on the mV\/UO knob)<br \/>\n<code>B = 100<\/code> (exponent for sensitivity of transducer)<br \/>\n<code>C = 1<\/code> (Units Out setting from lower left knob)<\/p>\n<p>Hence<\/p>\n<p><code>Sp = 1000 x 10^(-3) x 100 \/ 1<\/code><br \/>\n<code>Sp = 100<\/code><\/p>\n<p>The level in engineering units is obtained by dividing the voltage by Sp<\/p>\n<p><code>EU Level = (Measured Volts) \/ Sp<\/code><\/p>\n<p><a href=\"#top\">Back to top<\/a><\/p>\n<hr \/>\n<\/div>\n<div>[ <a href=\"?page_id=1120\">FAQ index<\/a> ]<\/div>\n","protected":false},"excerpt":{"rendered":"<p>Questions How do the units on the B&amp;K 2635 charge amplifier work Answers How do the units on the B&amp;K 2635 charge amplifier workThe knobs <span class=\"ellipsis\">&hellip;<\/span> <span class=\"entry-more-link-wrapper\"><a href=\"https:\/\/www.noiseboard.com\/?page_id=1230\" class=\"entry-more-link entry-more-link-excerpt btn btn-primary\"><span>Read More<\/span><\/a><\/span><\/p>\n","protected":false},"author":2,"featured_media":0,"parent":1120,"menu_order":0,"comment_status":"open","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-1230","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.noiseboard.com\/index.php?rest_route=\/wp\/v2\/pages\/1230","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.noiseboard.com\/index.php?rest_route=\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/www.noiseboard.com\/index.php?rest_route=\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/www.noiseboard.com\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.noiseboard.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1230"}],"version-history":[{"count":4,"href":"https:\/\/www.noiseboard.com\/index.php?rest_route=\/wp\/v2\/pages\/1230\/revisions"}],"predecessor-version":[{"id":1333,"href":"https:\/\/www.noiseboard.com\/index.php?rest_route=\/wp\/v2\/pages\/1230\/revisions\/1333"}],"up":[{"embeddable":true,"href":"https:\/\/www.noiseboard.com\/index.php?rest_route=\/wp\/v2\/pages\/1120"}],"wp:attachment":[{"href":"https:\/\/www.noiseboard.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1230"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}