EEVblog Electronics Community Forum
Products => Test Equipment => Topic started by: nickm on August 08, 2014, 02:52:25 am
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I haven't seen someone take apart the Tektronix isolated scopes so I thought I would take apart mine. The TPS series' inputs are completely floating so each channel is basically a differential amplifier. These are great for measuring primary and secondary waveforms at the same time. They are also battery powered so they're portable and you don't have to worry about being connected to mains.
(http://i.imgur.com/1Dtnlnf.jpg)
(http://i.imgur.com/Ng5KjC2.jpg)
BNC shells are covered with a black plastic. My guess is they need to cover any exposed metal to achieve safety ratings.
(http://i.imgur.com/8A1yUza.jpg)
Back cover removed.
(http://i.imgur.com/BQIZNie.jpg)
Each channel has isolation slots with plastic barriers between them. This side seems to be all the signal acquisition. Looks like it converts it to digital and then sends it over the isolation barrier to the main uC.
(http://i.imgur.com/FkxJv3g.jpg)
Front side of PCB.
(http://i.imgur.com/iWbmbXm.jpg)
Each channel has its own power supply which has completely isolated outputs. Looks like a multioutput flyback due to simplicity and to conserve space.
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Thanks, Nick. I've never seen the insides of one of those before.
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Do you have a link to higher res images. Looks very similar to the THS series scope frontends. An optocoupler is used for DC-1mhz and the rf transformer carrys the AC component.
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I used this scope recently. The ability to take floating differential measurements was quite useful because I was working on a high-side driver with high common-mode biases.
What I didn't like about it was the speed. This sort of Tek scope has a "save all" feature which saves the four channels (frustratingly in separate CSV files) and also a useful jpg screenshot. But when you use it on this scope, you have to twiddle your thumbs for 45 seconds while it writes to a CF Card (do they even make those any more??)
I really want a scope like this, but with much more responsive/faster user interface, and faster data storage, on a USB stick.
Unfortunately the newer scopes seem to run Windows, or have added bells and whistles that I don't want, like logic analysis, speak/interpret digital data bus signals, touch screen, etc.