EK020 Latching Relay

Part.no: 41016514

EK020 is a relay with latching function and will toggle the contact each time the toggle input goes high or the push button is pressed. One push on the button will activate the relay, another push deactivates.

The relay can be triggered from external signals (low: 0-5V / high: 6-12V). The available inputs are toggle, set (force on) and reset (force off).

EK020 can be used for starting a device from a small button or logic signal.

A solder jumper on the back side can be configured to force the relay to always start on or off. The jumper is pre-configured to force the relay to start off when the board is powered up.

The toggle input is filtered to prevent multiple toggles from contact bounces or noisy signals. Maximum toggle frequency is ~2 times/s.

The set and reset inputs are not filtered as they are triggered once on every positive going flank. All inputs are pulled to ground using 100kohm resistors and can be left floating when unused.

Supply voltage: 12VDC
Current draw: 40mA max.
Relay contact: 10A / 240VAC, 30VDC
Dimensions: 45.7 x 35.5mm
Mounting holes: c-c 40.6 x 30.5mm, ø2.5mm

Component list

RefDes	Value	Qty.	Part.no.	Marking
C1, C4	El.lyt capacitor 4.7uF	2	40520014	4.7uF
C2, C3, C5	Keramisk capacitor 100nF	3	41003038	104
CON1	Screw terminal 5.08mm 3-pol	1	41016291
D1	Diode BAT42	1	40311042
K1	Relay SRD 12V SPDT	1	40230002	SRD-12VDC-SL-C
LED1	LED 3mm red	1	40307000
R1, R4, R5, R6	Resistor 100kohm	4	40811510
R2	Resistor 1kohm	1	40811310
SW1	Push button off-(on) 6mm	1	41001617
T1	Transistor N-ch 2N7000	1	40327000	2N 7000
U1	Flip-flop D-type 4013B	1	40360030	CD4013BE

Assembly guide

Before starting the assembly, check that the PCB is free from damage and scratches. Verify that you have all the components to be assembled, compare with the component list!

It is easiest to start by mounting the lowest components and work upwards in size. Begin by soldering the IC socket in place, then continue with the resistors and the diode.

Once the IC socket, resistors and diode are in place, continue with the LED, the ceramic capacitors, the transistor and the push button.

Finish with the electrolytic capacitors, screw terminal, pin header and finally the relay.

When all components are in place and connectors or wires have been soldered, the logic IC can be mounted in the IC socket. Make sure all pins are aligned correctly with the socket and are not bent. Also pay attention to the orientation! Compare the marking on the PCB with the IC.

Interactive assembly guide ↗

Usage

The solder jumper marked "Start" on the back side can be configured in three ways and configures how the relay should behave when the board is powered up.

The jumper is normally connected in "OFF" mode. To change mode, cut the trace from the center pad. To connect ON or OFF, simply bridge the pads using solder.

OFF: always start with relay off (COM -> NC connected) Ingen: starts in undefined state, most times off ON: always start with relay on (CON -> NO connected)