{"id":72,"date":"2010-06-23T00:00:06","date_gmt":"2010-06-23T00:00:06","guid":{"rendered":"http:\/\/labrigger.com\/blog\/?p=72"},"modified":"2010-06-23T00:00:06","modified_gmt":"2010-06-23T00:00:06","slug":"a-ttl-operated-switchfor-coaxial-cables","status":"publish","type":"post","link":"http:\/\/labrigger.com\/blog\/2010\/06\/23\/a-ttl-operated-switchfor-coaxial-cables\/","title":{"rendered":"A TTL-operated switch
for coaxial cables"},"content":{"rendered":"

\"\"<\/a>
\nThis is a little gadget I find handy sometimes. It lets me use a TTL line to select between two routes for a coaxial cable. It’s dirt simple– just an SPDT relay– and I’ve coded the inputs by their location on the enclosure: the switch-operating input is by itself on the front, and the common pole is on one side, while the two throws are next to each other on another side. I use this to quickly switch between different signals for the oscilloscope, different synchronization schemes depending on my experiment protocol, and fast changes between different amplifier outputs. I put a magnet on the back of it, so that I can stick it to an equipment rack, Faraday cage, or optical table.<\/p>\n

Wire all the grounds together, then wire the center pins of the coax connectors to the relay pins as indicated in the datasheet. I used a 5v relay from Omron. (datasheet)<\/a><\/p>\n

\"\"<\/a><\/p>\n

It couldn’t be simpler. A different choice of relay and\/or additions to the circuit could allow it to operate at lower voltages (5v is at the top end of TTL specs) and\/or draw less current. The version I show here has worked with National Instruments DAQ digital outs and is clean enough for analog signals from PMTs and electrophysiology amplifiers. Keep all the wires short and use a metal enclosure.<\/p>\n","protected":false},"excerpt":{"rendered":"

<\/a>
\nThis is a little gadget I find handy sometimes. It lets me use a TTL line to select between two routes for a coaxial cable. It’s dirt simple– just an SPDT relay– and…<\/p>\n

Read More<\/a><\/div><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[6],"tags":[13],"class_list":["post-72","post","type-post","status-publish","format-standard","hentry","category-hardware","tag-gadgets"],"_links":{"self":[{"href":"http:\/\/labrigger.com\/blog\/wp-json\/wp\/v2\/posts\/72","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/labrigger.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/labrigger.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/labrigger.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/labrigger.com\/blog\/wp-json\/wp\/v2\/comments?post=72"}],"version-history":[{"count":10,"href":"http:\/\/labrigger.com\/blog\/wp-json\/wp\/v2\/posts\/72\/revisions"}],"predecessor-version":[{"id":135,"href":"http:\/\/labrigger.com\/blog\/wp-json\/wp\/v2\/posts\/72\/revisions\/135"}],"wp:attachment":[{"href":"http:\/\/labrigger.com\/blog\/wp-json\/wp\/v2\/media?parent=72"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/labrigger.com\/blog\/wp-json\/wp\/v2\/categories?post=72"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/labrigger.com\/blog\/wp-json\/wp\/v2\/tags?post=72"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}