Narda-STS is the world’s leading manufacturer of EMF (Electro-Magnetic Fields) safety equipment
Products include Broadband and Narrowband Field Survey Equipment, Personal Monitors and Area Monitors.
The company also offers various training courses for RF workers and Health and Safety management personnel..
Narda Satellite Networks is a manufacturer of high-quality satellite communications
equipment for the MilSatcom environment.
Narda Microwave West specializes in space qualified microwave assemblies, custom
laboratory grade RF amplifiers, filters, duplexers, isolators, circulators and other
standard and custom offerings from 250 MHz to 75 GHz.
Stocked Electro-Mechanical Switches (SEM Series)
For viewing, printing or downloading detailed technical information for our great variety of products and services, please select one of the product sub-category links (red type) on the navigation bar to the left.
Glossary
SP2T – A single-pole, double-throw switch has one input port and two selectable output ports.
Multiposition Switch – A multiposition switch has one input port and more than two selectable output ports. Unlike some switches, Narda models can be switched directly to any one of the available output positions without sequencing through intervening positions.
Transfer Switch – A transfer switch has two independent paths that operate simultaneously in one of two selected positions.
Failsafe – The switch moves to the closed position when the actuating voltage is applied and always returns to a predetermined position when the voltage is removed.
Latching – Also called Pulse Latching, the switch remains in a preselected position whenever the actuating voltage is removed or interrupted and holds that preselected position until a voltage is applied to another position. This configuration must be pulse-controlled with a pulse width of 20 ms to 100 ms duration. Standard polarity is common positive.
Normally Open – All output ports of the switch are disconnected from the input port until a voltage is applied to a selected position.
Terminated Units – Each unused or open output RF port is internally terminated in a 50-ohm resistive load (1W CW max.).
TTL – Selected position of the switch is controlled by a TTL Logic High. The switch requires only nominal +28 Vdc (additional 5 Vdc is not required).
TTL Logic Voltage Level:
Low 0 to 0.8 Vdc High 2.5 to 5.0 Vdc
TTL Logic Input Current:
Low 0 mA High 1.6 mA max. @ 3.85 Vdc
TTL Units – Transistor-Transistor-Logic circuitry enables the status of the switch to be controlled by the level of TTL logic input.
Suppression Diodes – Fast-recovery silicon rectifiers (diodes) connected in parallel with the coils of the switch to suppress any transient voltage that may be generated by the coils.
Indicator Circuitry – A set of internally mounted contacts that allows external monitoring of switch RF status. Some switch series include a steering diode drive due to the electronic indicator.
Solder Terminal – A turret terminal is standard on all switches.
Self De-energizing Circuitry – With this option, a set of internally mounted contacts or electronically generated pulses disconnects the driver voltage as soon as RF contact has been made. This option is only available with latching type switches. Suppression diodes must be specified with this option.
