The Application of Dry Reed Relays in Static Electricity Metering Circuits

Modern static electricity meters are highly sensitive electronic voltmeters with input impedance so high that in most practical applications, current flowing into them can be considered negligible. The actual input resistance of modern electronic static electricity meters is approximately 10^14 Ω. Due to the extremely high input impedance, special design considerations must be taken to avoid leakage current, such as using high-insulation relays in the driving circuit.

In addition to other applications, static electricity meters are also used in radiation detection in nuclear physics experiments. The radiation passing through the gas cylinder causes ionization of the gas in contact with it, producing very small currents. These currents are detected, amplified by an operational amplifier, and then quantified for early warning of radiation levels. However, semiconductor devices typically have too much capacitance, which “drowns” these small signals, and mechanical relays have too much leakage current and require the thin film on the contacts to be destroyed in order to allow current to pass, making them incapable of producing small signals. The only switch that can be applied in this environment is a dry reed relay. The HVFR-HI series relay recently designed by the MICAEL company is perfectly suitable for this application.

HVFR-HI Series High Insulation Dry Reed Relay

● Contact form: 1A/2A/3A/4A

● Switching voltage up to 1KV, instantaneous up to 2KV

● Switching current 1A, pulse current 5A/10A/20A

● Withstand voltage of 3KV or more. Insulation resistance above 100T

● Switching time less than 1.2ms, operating life over 1 billion times

The following advantages are obtained by using the HVFR-HI series high insulation relay:

  1. Excellent insulation performance with insulation resistance up to 100 Tohm, providing good isolation. Traditional mechanical relays cannot achieve such high insulation resistance.
  2. The contact is completely sealed and not affected by dust or water vapor corrosion, making the product suitable for use in some harsh detection environments.
  3. The special contact material makes HVFR-HI particularly suitable for switching control (signal switching) of weak currents from the acquisition end.
  4. It has a certain ability to withstand voltage, with a breakdown voltage of up to 3KVDC.
  5. High reliability and long life (billions of operations).
  6. Compact structure, small size, and can be installed in limited space, making it suitable for miniaturized equipment.
  7. Multiple contact forms (standard with 1-4 paths) are available for selection.