Model：520 Measurement Range  
0 to ±2 kV DC.

Model 523 Measurement Range  
0 to ±20 kV DC. 

Model：520 Probe-to-Surface Separation (recommended) 
5 mm to 25 mm.

Model 523 Probe-to-Surface Separation (recommended) 
30 mm to 60 mm.

The TREK Model 520 Hand-Held Electrostatic Voltmeter (ESVM) Series products provide accurate, noncontacting measurements of electrostatic surface voltage for ESD applications in either ionized or non-ionized environments. Industrial applications include measuring charge accumulation in the LCD manufacturing process or measuring static charge in semiconductor production. The Model 520 series ESVMs utilize a new measurement technique that overcomes the disadvantage of the typical hand-held fieldmeter by providing surface voltage measurements which are essentially independent of the sensor probe-to-measured surface spacing.

Model：520-1 ESVM 
Over a spacing range of 5 mm to 25 mm, the 520 voltmeter provides better than a 5% voltage measurement accuracy, while the typical fieldmeter provides a voltage measurement error in excess of 50%. An optional voltage monitor output is available (Model：520-2).  

Model 523 ESVM
Over a spacing range of 30 mm to 60 mm, the 523 voltmeter provides greater than a 5% voltage measurement accuracy, while the typical fieldmeter provides a voltage measurement error in excess of 50%. 

The 520 series provides a measurement system which complies with standardized calibration equipment traceable to the National Institute of Standards and Technology. The 520 series hand-held voltmeters employ a slender sensor probe design that provides flexibility to make measurements in many locations which are impossible to reach using the large, bulky sensing surfaces of the typical hand-held fieldmeter. The slender design also allows for higher spatial resolution capability by allowing the measurement of small surface areas. A "hold" pushbutton retains the displayed measured voltage value for recording purposes.

 

Model：520 Measurement Range  
0 to ±2 kV DC.

Model 523 Measurement Range  
0 to ±20 kV DC. 

Model：520 Accuracy  
ESVM Monitor (Model：520-2)  
Better than ±5% of full scale over the entire recommended probe-to-surface separation range of 5 mm to 25 mm.

Model 523 Accuracy  
Better than ±5% of full scale over the entire recommended probe-to-surface separation range of 30 mm to 60 mm. 

Model：520 Probe-to-Surface Separation (recommended) 
5 mm to 25 mm.

Model 523 Probe-to-Surface Separation (recommended) 
30 mm to 60 mm.

Stability  
Drift with Time  
Less than 600 ppm/hour, noncumulative. 
Drift with Temperature  
Less than 600 ppm/°C.