I need to control with my Arduino some galvanometers I bought. The galvanometer driver board says it need to have a +-5V asymmetrical analog input.

My Arduino is connected to a MCP4922-E/P DAC from Microchip through SPI. The output of the MCP4922-E/P is between 0 and +10V (it can be between 0 and +5V if I don't enable the x2 gain).

How can I "lower" that signal to be between -5V and +5V? I've read the it could be done with some op-amp, but not sure how.

Any other advice about the design is welcome. Thanks in advance.


opamp is one idea - there are plenty of tutorials in the internets, but it might be easier to connect GND of your galvo to +5V. If you don't have +5V, you can make it from your +10V.

  • \$\begingroup\$ Thanks for your answer. Could you please point me one, or at least what I must look for? For example, in en.wikipedia.org/wiki/Operational_amplifier_applications I can see a lot of things that can be done with a Op-Amp, but which one could be usefull for what I'm trying to do? \$\endgroup\$ – Havok Mar 14 '11 at 4:09
  • \$\begingroup\$ "Differential amplifier". You put some reference voltage on one of inputs, fed your signal into second, and tune resistors to get output range you want. \$\endgroup\$ – BarsMonster Mar 14 '11 at 8:03
  • \$\begingroup\$ Great! Thank you very much, that's what I was looking for. \$\endgroup\$ – Havok Mar 14 '11 at 16:29

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