Bourns Model 1840 DIN Rail Signal & Data Line Protectors

Bourns 1840 Model Signal and Dataline Protectors are high performance Surge Protection Devices (SPD) designed to protect sensitive electronic circuits and components from damaging surge voltages and currents. Features include low peak clamping voltage, ability to repeatedly protect against surge, convenient DIN-1 and DIN-3 rail mounting, and cable shields that may be either grounded or arc-protected to ground. The device's extremely fast response and low clamping voltages make the series well-suited for the protection of sensitive signal and datalines associated with computer, data communication, instrumentation, broadcasting and industrial controls. The devices may be used directly with EIA standard interfaces RS-232, RS-422, RS-423, RS-485 and with 4mA to 20mA and 50mA instrumentation loops. The Model 1840 Model Signal and Data line Protectors are fast, rugged, and capable of protecting against fast rising voltage transients as well as the severe current surges associated with lightning discharges, in each case up to rated limits.


  • Low peak clamping voltage even during severe current surges
  • Ability to repeatedly protect against surge currents in excess of 10,000A
  • Convenient mounting and grounding to any flat surface or to DIN-1 (TS-32) or DIN-3 (TS-35) rail
  • Cable shields are passed through and may be either grounded or arc-protected to ground
  • Vibration-resistant screw-type clamp terminals
  • Flame-resistant epoxy-filled housing


  • 12Ω typical series resistance
  • 220mA max. load continuous current
  • <10μA DC leakage current at rated L/G voltage
  • Typical 450mA blocking current
  • 3db @ 30MHz with 50Ω termination signal/data attenuation
  • -40°C to +60°C operating temperature range
  • <1μsec response time
  • 20AWG wire size


  • Computers
  • Data communication
  • Instrumentation
  • Broadcasting
  • Industrial controls

Circuit Diagram

Application Circuit Diagram - Bourns Model 1840 DIN Rail Signal & Data Line Protectors
Published: 2014-03-27 | Updated: 2022-03-11