Sensitive Research ESD Electrostatic Voltmeter 0-5000V Double Pivot 1MHz

Sensitive Research ESD Electrostatic Voltmeter 0-5000V Double Pivot 1MHz

The Sensitive Research Instrument Corporation Model ESD is a Double Pivot Electrostatic Voltmeter designed to measure high AC and DC voltages across a range of 0 to 5,000 volts. Unlike moving-coil meters, electrostatic voltmeters draw virtually no current from the circuit under test — making them well suited to measuring high-impedance sources, high-voltage AC circuits, and static charge levels without loading the circuit. This example was standardized on December 16, 1935, and is housed in its original wooden carrying case.

Specifications & What's Included

• Manufacturer: Sensitive Research Instrument Corporation
• Model: ESD
• Serial Number: 60420
• Meter type: Double Pivot Electrostatic
• Voltage range: 0–5,000 Volts
• Frequency range: To 1,000,000 Hz (1 MHz)
• Accuracy guarantee: 1% of full scale
• Temperature correction: (1 −.0004(T − 25°C)) × Reading
• Maximum overload: 20%
• Connections: HIGH SIDE and LOW SIDE OR GROUND binding posts (left side panel)
• Display: Arc-scale analog meter face with VOLTS scale
• Enclosure: Original hinged wooden carrying case with brass latch hardware
• Lid interior: Original Sensitive Research Instrument Corporation data/calibration plate, intact and fully legible
• Date standardized: December 16, 1935
• Includes: Instrument in wooden case — no cables or accessories included

Applications

Electrostatic voltmeters like the Sensitive Research Model ESD were a standard laboratory instrument from the early twentieth century through the mid-twentieth century, used wherever accurate, high-impedance voltage measurement was required. Because they operate on the principle of electrostatic attraction between charged plates — drawing essentially zero current from the source — they are particularly useful for measuring high voltages on capacitive or high-resistance circuits where a conventional moving-coil instrument would distort the reading by loading the circuit. The ESD's range to 5,000 volts and frequency response to 1 MHz made it suitable for AC power laboratory work, high-voltage testing, and early radio and electronics research. Sensitive Research Instrument Corporation, based in New York, was one of the leading American makers of precision electrostatic instruments from the 1920s through the mid-twentieth century; their instruments were commonly found in utility company labs, university physics departments, and industrial high-voltage test facilities. Today these instruments are sought by collectors of vintage test equipment, science museums, and enthusiasts of early electrical metrology.