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Relay Technology for High Power Switching Applications
Reed relays are usually associated with low level applications, where their unique attributes provide performance advantages compared to other switching technologies. However, they are widely used in areas where higher power levels within their maximum ratings need to be switched or where the requirement is carry current, either continuous or pulse. In semiconductor testing, there can be a wide range of signals from millivolts to kilovolts, picoamps to amps and the construction of a reed relay can mean it can accommodate all of these.
This is something many users in a wide range of industries have discovered, from established ones like semiconductor and equipment testing, to new areas such as renewable energy and space. In these, and many other applications, the advantages of a reed relay can result in enhanced overall performance.
Reed relay operating speeds can be 10 times faster than even a small electromechanical relay, greatly reducing cycle times, and with no mechanically operated moving parts, the mechanical life can be 1000 times longer. With reed relay contacts sealed in either an inert gas or a vacuum, there are no issues with oxidation of the contact surfaces which can seriously affect the ability of electromechanical relays to switch low levels, many often specifying a minimum switched current which is not a concern for a reed relay.
Compared to semiconductor switches, the off-state leakage currents for a reed relay can be picoamps(pA) compared to microamps(mA) for a solid-state device, and the capacitance between the connections can be 100s of picofarads(pF) compared to a reed relay which can be lower than 1 picofarad. For many semiconductor switches, the on resistance can be much higher when compared to either reed or electromechanical relays. Furthermore, reed relays boast impressive standoff capabilities, reaching over 15kV, with even miniature parts withstanding up to 5kV. This far surpasses the limitations of both electromechanical relays and semiconductor switches, which can be limited to 1kV to 1.5kV.
These advantages have helped users find superior alternatives to their existing switching technologies, particularly when seeking improvements in overall performance. For instance, in mixed-signal semiconductor testing, the high-voltage performance of reed relays has successfully addressed the limitations posed by solidstate relays, thereby enhancing testing capabilities in critical areas.
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Download the full application guide now to learn more about utilizing relay technology in higher power applications.
Contents of the application guide:
- Selecting Your Relay Technology
- Updating from Mercury Wet Relays
- Relay Technology Life Expectancy
- Comparing Relay Technologies
- Reed Relay Terminology
Recommended Reed Relays for use in High Power Applications
Series 144 - Up to 80W
The 144 relays boast a power rating up to 80W with switch current of up to 2A, and the maximum carry current is 3A. Can replace mercury wet reed or miniature EMRs. Additionally, they’re suitable for high voltage applications with a maximum switching voltage of 1kV up to 10W and the option of 2kV or 3kV standoff. Available forms: 1 Form A, 2 Form A, and 1 Form B contact configurations.
Series 114 - Up to 40W
The 114 relays have a power rating up to 40W with switch current of 1A, and the maximum carry current is 3A. Switches feature sputtered ruthenium contacts suitable for low level or dry switching. They switch AC mains voltages, making them ideal for interfacing with larger electromechanical relays. Available forms: 1 Form A, 2 Form A, and 1 Form B contact configurations.
Series 100HC - Up to 40W
The 100HC relays have a power rating up to 40W, maximum switch current is 1A, and 3A continuous carry current with even higher levels in pulsed current applications. High coil resistance of up to 6000Ω for low power consumption. Thermal EMF levels less than 10μV Available forms: 1 Form A, 2 Form A, and 1 Form B contact configurations.
Series 67 - Up to 200W
These Series 67 relays feature the highest power switch in the Pickering portfolio with a power rating up to 200W. Switch current is 3A, and the maximum carry current is up to 5A. They are also suitable for high voltage applications with a stand-off voltage of up to 8kV, and capable of 6kV switching. Available forms: 1 Form A and 1 Form C contact configurations.
