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FAQ02822 of General Purpose Relays FAQ

FAQ No. FAQ02822

Primary Contents

Question

What's a latching relay?

Answer



It is a relay that is set (ON) or reset (OFF) by the input of a pulse voltage. Even after the input voltage is interrupted, this relay maintains its set or reset condition until it receives the next inverting input. It is also called a keep relay.

There are two types of mechanisms for maintaining the set and reset conditions:

a magnetic holding type and a mechanical holding type.

There are also two types of coils for applying the set and reset pulse voltages:

a single-winding type and a double-winding type.

Basic Operation:

ItemBasic circuitOperation patternOutline
Classification
Double-
winding
Latching
Relays
In these Relays, the input
pulse of the set coil causes
the operating condition to
be maintained magnetically
or mechanically, whereas
the input pulse to the reset
coil side puts the Relay into
the reset condition.
Single-
winding
Latching
Relays
In these Relays, the set
input pulse causes the
operating condition to be
maintained magnetically,
whereas the reset input
pulse (input with inverse
polarity of set input) puts
the Relay into the reset
condition.

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