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mxmxmx / temps_utile-

teensy 3.2 trigger generator
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Changing voltage levels of clock outputs #55

Closed denniskulpa closed 2 years ago

denniskulpa commented 2 years ago

Reading a comment in the BOM regarding the clock output levels:

"the (digital) clock outputs are non-inverting op amps, the values on the pcb (20k feedback, 10k to ground) will result in 3x gain, or 9.9v on the outputs. adjust, if you like. for example, 15k would give you 3.3v * (20k/15k + 1) = 7.7, etc."

I'm thinking about doing this (lowering them, closer to 5-6V). Since there isn't a firm schematic, I've traced the paths on the PCB, verified with a multi-meter, it looks like I'd have to change the resistors highlighted in RED on this layout:

TEMPS-UTILE

I would leave the DAC output as-is, just alter the outs for the other five channels (1, 2, 3, 5, & 6). Are these the correct components to change? If not, what are the correct resistors?

TIA, Dennis Kulpa

denniskulpa commented 2 years ago

Just following up, those are the correct resistors to change. I used 20K resistors in place of the 10K called for in the BOM, I'm getting 6.8V triggers out of the 5 channels. Only been running it for about 2 hours but, so far, I have not had any problems triggering modules in my rack; we'll see what happens.