Question about 555 timer circuit with relays - diyAudio
Go Back   Home > Forums > Design & Build > Parts

Parts Where to get, and how to make the best bits. PCB's, caps, transformers, etc.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 1st March 2003, 10:32 AM   #1
Ralph is offline Ralph  Netherlands
diyAudio Member
 
Ralph's Avatar
 
Join Date: Apr 2002
Location: Culemborg, The Netherlands
Default Question about 555 timer circuit with relays

I found a nice delaying circuit to switch on the B+ circuit of my PSU. It's just what I need:

http://www.ultranalog.com/schem/hvdelay.pdf

I have 4 circuits I want to switch on, all 5V/2A for the 4 rectifier tubes: http://www.homepages.hetnet.nl/~rjonkers/psu.gif

I'm planning to use 4 of these 12V relays http://www.farnell.com/datasheets/7611.pdf that consume 360mW each

* Now my question, can I switch all 4 relays with just a single 555 circuit, or do I need to build 4 circuits like the one above?

* Is it ok to use 13.7v at the input of the circuit (then I will have 12v for the relay as the 555 drops 1.7v)?

Thanks, Ralph
  Reply With Quote
Old 1st March 2003, 10:45 AM   #2
diyAudio Member
 
Join Date: Nov 2001
Location: Haarlem
Send a message via MSN to blank527
Hi,

For your questions

1 - No I wouldn't do that, because you source the output to much and the 555 will break.
I should put 4 BC560 in parallel and with higher input ressistor (not much)

2- The 555 has a large range of operating voltages, but I would put some stabillity around this IC.. beceause it could affect the output. some elco's close to the IC power should do this job.

Last.. read the datasheet for timing, when the relays comes up.


Grtz,
Remco Blankesteijn
  Reply With Quote
Old 1st March 2003, 11:02 AM   #3
Electrons are yellow and more is better!
diyAudio Member
 
peranders's Avatar
 
Join Date: Apr 2002
Location: Göteborg, Sweden
Blog Entries: 4
I don't agree with Mr. Blank.

First of all: You must get the datasheet of the same brand as the one you have. LM555 isn't exactly the same if we talk ON, National etc. certainly not the CMOS type.

If we take National:

16 volt max as supply voltage and absolute max is 18 V.

Max current is 200 mA, your load is 120 mA.

The only thing you have to think about is to add a diode 1N4001-7 across the relay coils, cathode towards +.

Let me also add, it isn't wrong to be a little bit cautious, a separate transistor doesn't hurt.
__________________
/Per-Anders (my first name) or P-A as my friends call me
Super Regulator SSR03 Group buy
  Reply With Quote
Old 1st March 2003, 11:09 AM   #4
Ralph is offline Ralph  Netherlands
diyAudio Member
 
Ralph's Avatar
 
Join Date: Apr 2002
Location: Culemborg, The Netherlands
The IC will be a PHILIPS SEMICONDUCTORS, Manufacturer Part Number NE555N. Maybe I should look for a relay that consumes a little less power.
  Reply With Quote
Old 1st March 2003, 11:19 AM   #5
Keld is offline Keld  Sweden
diyAudio Member
 
Keld's Avatar
 
Join Date: Jan 2002
Location: Borås, Sweden, Tellus
Default Re: Question about 555 timer circuit with relays

Quote:
Originally posted by Ralph
SNIP
* Now my question, can I switch all 4 relays with just a single 555 circuit, or do I need to build 4 circuits like the one above?

SNIP
Thanks, Ralph
Or you can let one (smal) relay operate the other 4.

Keld
  Reply With Quote
Old 1st March 2003, 11:21 AM   #6
Electrons are yellow and more is better!
diyAudio Member
 
peranders's Avatar
 
Join Date: Apr 2002
Location: Göteborg, Sweden
Blog Entries: 4
Quote:
Originally posted by Ralph
The IC will be a PHILIPS SEMICONDUCTORS, Manufacturer Part Number NE555N. Maybe I should look for a relay that consumes a little less power.
If Philips also can deliver 200 mA I see no reason why you can use a 120 mA load (4 x 0.36/12).
__________________
/Per-Anders (my first name) or P-A as my friends call me
Super Regulator SSR03 Group buy
  Reply With Quote
Old 1st March 2003, 01:39 PM   #7
dhaen is offline dhaen  Europe
diyAudio Moderator Emeritus
 
dhaen's Avatar
 
Join Date: Jun 2002
Location: U.K.
Ralph,

Why so many relays?
Surely you just need 1 x 2-pole relay per monoblock.
It is only necessary to interrupt 1 heater connection on each rectifier

Cheers,
  Reply With Quote
Old 1st March 2003, 02:42 PM   #8
Ralph is offline Ralph  Netherlands
diyAudio Member
 
Ralph's Avatar
 
Join Date: Apr 2002
Location: Culemborg, The Netherlands
Hi John

I selected two 2-pole relays from Farnell:

959-455 DPCO, 10A - 44.62 Series
http://www.farnell.com/datasheets/4039.pdf

and

431-382 DPCO, 8A - 40.52 Series
http://www.farnell.com/datasheets/396.pdf

both are rated as 55mA consumption (so 110 together, which is way within the 200mA 555 specs). Will they both be ok?
  Reply With Quote
Old 1st March 2003, 04:53 PM   #9
dhaen is offline dhaen  Europe
diyAudio Moderator Emeritus
 
dhaen's Avatar
 
Join Date: Jun 2002
Location: U.K.
Ralph,

I think the relays willl be OK. But why 2?

Cheers,

PS Don't forget to add a reverse biased diode across the coil.
  Reply With Quote
Old 1st March 2003, 05:48 PM   #10
Ralph is offline Ralph  Netherlands
diyAudio Member
 
Ralph's Avatar
 
Join Date: Apr 2002
Location: Culemborg, The Netherlands
Well, the 300B circuit has 2 rectifiers (L+R) and so has the 5687 circuit. That makes 4 high voltage circuits and therefor I need two 2-pole relays.

And I won't forget the diode, it's in the schema I'll build (D1) http://www.ultranalog.com/schem/hvdelay.pdf
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Soft-start circuit with no relays and no aux. transformers Eva Power Supplies 74 12th August 2014 10:32 PM
Do I need a Timer Circuit? silentblackhat Digital Line Level 4 1st February 2009 09:16 PM
quick question about tube relays Scott_fx Tubes / Valves 10 19th October 2006 07:32 PM
Question about automotive relays?? jaygeorge1979 Car Audio 4 21st April 2006 02:23 AM


New To Site? Need Help?

All times are GMT. The time now is 02:40 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright ©1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2