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Date: 11/11/02 at 7:19 AM
Posted by: David Ashby
E-mail: dashby@quin.co.uk

In Reply to: D/A card providing max of 2mA, need more current. posted by alan on 11/08/02 at 6:07 PM:

Hello Alan,

First, some answers to your questions:

1) No. You need an amplifier that has sufficient output current capability

2) This isn't a difficult problem. If you have some basic knowledge about power op-amps (or buffers), and can wire them up (inputs, outputs and suppliy voltages), then all you'll need is pointing in the right direction. If you're at a loss when it comes to the practicalities of circuit construction, soldering, etc you'll need to get 'hands-on' help.

Basically, if you have a 45ohm load that you want to drive up to 20V, you will need an amplifier capable of delivering nearly 0.5 amps (20V/45ohms). At the same time, it will have to be able to dissipate un-used power as heat. Here is a link to some useful background information:

http://www.web-ee.com/primers/files/DesignSem4.pdf

Hope this helps.

David Ashby

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