The variable gain transimpedance amplifier DHPCA-100 is suitable for small currents generated by high-impedance sources, such as photodiodes and ionization detectors. Released by Femto Messtechnik GmbH, the device offers a maximum bandwidth of 200 MHz, which is equivalent to a rise time of 1.8 ns. The gain is adjustable from 102 to 108 V/A, allowing the measurement of currents in the subnano- to milliampere range. An adjustable voltage supply is provided as bias for external photodiodes. The amplifier has applications in spectroscopy, particle detection, and fast current and resistance measurements.