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Electrometers Use Reed Relays to Switch & Carry Low Signal in Their Detection Circuits

Reed Relays in Electrometer Detection Circuits

Introduction

Electrometers are used to measure ultra low currents at the sub-pico amp level.  These electrometers are often used in radiation detection, where the radiation going through a gas cylinder ionizes the gas it comes in contact with.  Ultra small currents are generated from the ionization, they need to be detected, switched into an operational amplifier, and then quantified for an early alert of the radiation level.  Semiconductors have too much capacitance literally ‘swallowing up’ these signals. Electromechanical relays have too much leakage current and the film buildup on the contacts that needs to be broken for current to flow, never happens with these small signals.  The only switch that can handle this environment is the Reed Relay.  MEDER’s specially designed reed relays meet the requirements necessary to switch and carry this low signals.

Full application write up:  Electrometers Use Reed Relays in Their Detection Circuits

Features

  • High quality and reliability
  • Very small size
  • Ability to switch up to 1 amp
  • Insulation resistance > 1012 Ohms typical with
    > 1014 Ohms available
  • Capable of switching and carrying up to 15 GHz
  • Dielectric strength across the contacts 200 volts
  • Contacts dynamically tested
  • Low stable contact resistance
  • Long life with up to a billion reliable operations

Through Hole Series & Axial
Relay SeriesDimensionsIllustration
mminches
HIW7.900.295HI Reed Relays
H7.500.311
L28.001.102

Surface Mount Series
Relay SeriesDimensionsIllustration
mminches
SRF           
W4.00.157SRF reed relay for RF
H3.20.126
L7.50.295
CRFW4.40.173CRF reed relay for RF
H3.50.137
L8.60.338