As a predecessor of M525, the M520 is very similar in circuitry, providing same accuracy and comparable parameters for less.
Sturdy mechanical knob design makes manual control pretty straightforward along with internal rechargeable battery make the M520 ideal for on site calibrations where grid power is not an option.
The Capacitance decade is supplied from internal battery.
External power adapter is used as external power source and as battery charger.
Connectivity
Even though the M520 looks mechanical, internal capacitance standards are switched electronically by relays.
This way we could fit it with RS232 remote control so it can be used in Caliber or any other automated calibration solution.
