Variable Gain Current Amplifiers

You know the routine. You have rigged up a prototype for your application. Your detector is doing what it does. Now all you need is a current amplifier so you can see (and measure) what is happening. The problem is which amplifier to go for? How much bandwidth do you need? How much gain do you need? You may not know at this stage, perhaps the theory does not reveal, or there may be a wide range of signal currents in your application, so which amplifier do you buy?

Well, if the detector has a high impedance for example a photodiode, PMT or ionisation detector, the answer is a variable gain current amplifier from FEMTO Messtechnik GmbH:

The DLPCA-200 has a transimpedance gain switchable from 1 x 10³ to 1 x 10¹¹ V/A with a bandwidth of DC to 500kHz. It has adjustable bias voltage and adjustable offset and switchable AC/DC coupling and switchable upper cut-off for DC measurements.

The DHPCA-100 has a transimpedance gain switchable from 1 x 10² to 1 x 10⁸ V/A with a bandwidth of DC to 200 MHz.

The DDPCA-300 has a transimpedance gain switchable from 1 x 10⁴ to 1 x 10¹³ V/A for sub-fA to mA measurements, with a bandwidth of DC to 400 Hz.

Then when you have finished, use them again for your next detector setup with different settings.