Coil and schematic - Page 1
Forum section: electronics / beginners

author: RobH
author_rank: Regular Contributor
timestamp: November 26, 2020, 11:30:30 am
content: i found this schematic, attached, for a IR sensor type circuit, and it has a coil/relay?? in it named as K1 on the schematic.I bought a 5A SPDT High Sensitivity Relay 5V dc Coil which has 6 pins, but I don't know which pin to connect to what in the said circuit.There is a youtube video on this circuit, but it goes into more about testing it rather than how to put it together, hence my doubts.Also the schematic shows a diode D1 going across the couil/relay, but I can't see it in the video.Thanks

author: Circlotron
author_rank: Super Contributor
timestamp: November 26, 2020, 11:40:01 am
content: Post the details of the relay you bought.

author: RobH
author_rank: Regular Contributor
timestamp: November 26, 2020, 12:34:03 pm
content: I bought the relay from an ebay seller, and all the details are on this page:https://www.ebay.co.uk/itm/5A-SPDT-High-Sensitivity-Relay-5V-dc-Coil-Ag-Alloy-Contacts-PE514005-Multi-Qty/302823093299?ssPageName=STRK%3AMEBIDX%3AIT&var=601723709856&_trksid=p2060353.m2749.l2649Thanks

author: Circlotron
author_rank: Super Contributor
timestamp: November 26, 2020, 12:57:24 pm
content: https://manualzz.com/doc/38947173/miniature-pcb-relay-pe

author: RobH
author_rank: Regular Contributor
timestamp: November 26, 2020, 01:05:53 pm
content: Ok, so it looks like a diode goes between A1 and A2, if I am reading it right. What of the other pins are the input and output in relation to the schematic.Thanks

author: lucatz
author_rank: Contributor
timestamp: November 26, 2020, 02:22:18 pm
content: Schematic seems to calls for DPDT (Double Pole Double Trough) But in the end SPDT may work if you only need one pole. Attached is what I think it should be. NO is Normally open, NC is Normally Closed, C is your common.So when IR beam is interrupted it will energize the relay which will make a new connection from C to NO, NC will become OPEN and break circuit of whatever is connected to it.. There need not be anything connected to NO.This can also be connected in reverse ie. when beam is interrupted the relay energizes and NO is now connected to C which can activate a siren or RED light.

author: RobH
author_rank: Regular Contributor
timestamp: November 26, 2020, 02:57:31 pm
content: I'll buy a DPDT relay then if that is what it should be.So is the transistor T2 connected to C on the relay, then which pin for the -V connection.Thanks

author: lucatz
author_rank: Contributor
timestamp: November 26, 2020, 03:43:37 pm
content: Coil of Relay gets connected to T2,this is what will energize you coil and activate the relay. C can be connected to 5V supply. Relay is just a switch activated by the COIL.

author: RobH
author_rank: Regular Contributor
timestamp: November 26, 2020, 05:10:16 pm
content: Ok thanks, but does it matter then what pin of the relay connects to T2

author: lucatz
author_rank: Contributor
timestamp: November 26, 2020, 05:57:51 pm
content: Yes Very,In your case since SPDT, see attached...

author: RobH
author_rank: Regular Contributor
timestamp: November 26, 2020, 06:47:14 pm
content: Thanks for that, and very clear now

author: james_s
author_rank: Super Contributor
timestamp: November 26, 2020, 08:03:54 pm
content: Quote from: RobH on November 26, 2020, 02:57:31 pmThat depends completely on what you intend to control with the relay. The circuit will activate the relay coil which will pull in the armature and move the contacts. The actual configuration of these contacts can be whatever you need. If you just want to turn something on when the relay is triggered then you only need a SPST contact but it's fine to leave extra contacts unconnected.