Relays, Timers & Bases

A relay is an electrically operated switch. It consists of a set of input terminals for a single or multiple control signals, and a set of operating contact terminals. The switch may have any number of contacts in multiple contact forms, such as make contacts, break contacts, or combinations thereof. Relays are used where it is necessary to control a circuit by an independent low-power signal, or where several circuits must be controlled by one signal.

We have an extensive line of Relays, Timers, Bases, and other Accessories. We also have a Cross Reference to more then 85,000 industry types from 267 different Suppliers. If you need a Timer for your Water Pump or an Automotive Relay for your Motorcycle,
Farnsworth Electronics has the Parts in Stock that YOU need.

Below is a category list of the NTE line of Relays we stock the most of. Click on each category for more information

We also carry brands such as: ABB, Amatek (National Controls), American Zettler, Amperite, Carlo Gavazzi, CIT Relay & Switch, Crouzet, Custom Connector, Deltrol Controls, Fuji Electric, Grayhill Electric, Honeywell, Idec, MARS, Omron, PanasonicStruthers-Dunn,  TE Connectivety, Weidmuller & others.

Looking for a Relay Glossary of Terms, Click Here

Relay Glossary Of Terms:

AC Operated Relays: These type of relays incorporate a shading ring on the pole face preventing total collapse of the magnetic field during zero voltagecrossover.Armature: The moving magnetic member of an electromagnetic relay structure.Break: The opening of closed contacts to interrupt an electric circuit.Bounce Time: Duration from the first to last making or breaking of a relay contact during one operation.Coil: An assembly consisting of one or more windings with terminals and any other required parts such as a sleeve or slug. The windings may be self supporting but usually are wound around an insulated iron core or on a bobbin.Contact: 1. A conductive connection of two elements. 2. A contact piece designed to ensure reliable current passage either in the form of a rivit or welded assembly.Contact Forms: Denotes the contact mechanism and number of contacts in the contact circuit.
Contact Symbols: See Below
Contact Life: The number of operations for a given contact load under specified conditions (e.g. duty cycle, maximum operating rate) without leading topermanent contact failure (e.g. contact welding, excessive contact wear/resistance or contact locking when switching DC loads).Contact Resistance: The electrical resistance of closed contacts.Continuous Current: The maximum current a relay may carry continuously without exceeding temperature limits.DC Relays: A relay with coils designed for operation from a DC supply.Dielectric Strength: The voltage which may be applied to two adjacent metal parts insulated from each other without causing electrical breakdown.
Drop Out (Release) Time: The time from removal of voltage from the coil circuit to the first breaking or making of the relay contact.Drop Out (Release) Voltage: The voltage at which the relay returns safely to its unoperated position.Duty Cycle: The ratio of operated time to the total cycle time expressed as a percentage.Electrical Life: Refer to “Contact Life”.Holding Current: Minimum coil current required to hold the armature in the operated position.Insulation Resistance: The resistance value between mutually isolated conducting sections of the relay (e.g. between coil and contacts, across open contacts, and between coil or contacts to any core or frame at ground potential). This value is usually expressed as “initial insulation resistance” and may decrease with time, due to material degradation and the accumulation of contaminants.Mechanical Life: The guaranteed number of operating cycles without load.Make: The closure of an open contact to complete an electric circuit.MBB Contacts: Abbreviation for make−before−break contacts. Contact mechanism where Form “A” contacts (normally open contacts) close before Form“B” contacts open (normally closed contacts).Normal Position: 1. The de−energized, unoperated position of contacts (open or closed) due to spring tension, gravity, or magnetic polarity. 2. The home position for a stepping switch.Nominal Coil Resistance: The DC coil resistance measured at its terminals at a winding temperature of +23 C.
Peak Make Current (Inrush Current): The maximum current flowing through a relay contact immediately after closure.Power Consumption (Total): Sum of nominal coil power consumption plus power consumed in any series resistor in Watts or VA.Pull In (Operate) Time: The time from application of voltage to the coil to first making or breaking of the relay contact.Pull In (Operate) Power: The power consumed by the relay coil in order to operate the relay.Pull In (Operate) Voltage: The minimum voltage required to operate the relay.Rated Current: 1. For a relay coil − the nominal voltage divided by the coil resistance. 2. For a contact − refer to “Continuous Current”. Rated Voltage, The reference voltage for the definition of other relay data.
Relay Life: Refer to “Electrical Life” and “Mechanical Life”.Relay Pole: A contact set comprising either a changeover or normally open, or normally closed contact. Relays with more than one pole can controlmore than one circuit.Switching Cycle: One cycle of energization and release of a relay.Switching Rate: Operating cycles per hour or per second.Switching Voltage: The voltage which appears on the contacts before their closing or after their opening after transients have disappeared.Temperature Compensation: With increasing temperature but constant coil voltage the magnetic field generated will be reduced due to a change in coil resistance (e.g. for enamelled copper wire approximately 4%/10 C). By incorporating a permanent magnet with an opposite temperature coefficient into themagnetic circuit, the pull in voltage of the relay may be kept stable over a wide temperature range.Thermal Resistance: Coil heating as a function of coil power consumption.Time Constant (Electrical): The time until the current reaches 63% of its final value after energization (ratio L to R). DC load handling capacity and life figuresare dependent on the L/R value of the DC load circuit.Total Contact Resistance: The sum of relay contact resistance plus resistance of connecting elements as measured on the relay terminals.
Contact Symbols: Form “A” contacts are also called N.O. contacts or make contacts. Form “B” contacts are also called N.C. contacts or break contacts.Form “C” contacts are also called changeover contacts or transfer contacts.

Relays, Timers, Bases & Accessories

Relay Glossary Of Terms:

The first to know!

Thank you!

Error