The essential details of the design along with an introduction to the peculiarities of high-impedance circuits have been presented elsewhere This will be expanded here Practical circuitry that reduces effective bias current for those applications where performance cannot be made dependent on offset current are described In addition circuits combining the DC characteristics of the new part with the AC performance of existing fast amplifiers will be shown This will be capped with a number of practical designs to provide some perspective into what might be done dc errors