A Direct-Coupled DC Amplifier Compensated to 20 kc for Use with Photoemissive Devices

The relative advantages of the use of a negative-feedback operational amplifier as an electrometer amplifier are investigated. This investigation was made because of the need for a detection system with a frequency response from dc to 20 kc. A theoretical analysis of the compensation circuits used to obtain extended frequency response is given. This analysis indicates a dependence of the compensation networks upon the external capacitive loading. Important practical considerations are given. An expression is derived that gives the compensation network parameters as well as the frequency response in terms of absolute gain of the amplifier.