The HP 3457A is a versatile high precision digital multimeter which measures ac or dc volts, ac or dc current, ac+dc volts or current, resistance, frequency and period. It measures voltages up to 300 Vac or 300 Vdc with high dc resolution and accuracy. The instrument is designed for both bench and system use. Program and reading storage are included to allow high speed measurement applications with reading rates of greater-than 1000 readings per second. Provision has been made for optional assemblies such as a general purpose scanner or multiplexer.