toggle circuit doesn't work - diyAudio
Go Back   Home > Forums > General Interest > Everything Else

Everything Else Anything related to audio / video / electronics etc) BUT remember- we have many new forums where your thread may now fit! .... Parts, Equipment & Tools, Construction Tips, Software Tools......

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 10th February 2007, 05:54 PM   #1
turner is offline turner  Germany
diyAudio Member
 
Join Date: Jun 2006
Lightbulb toggle circuit doesn't work

hi folks,

i build a toggle circuit to switch on my diy amp with a pushbutton (not a switch!). the toggle circuit is based on a 4027 mos, the circuit is shown below:

Click the image to open in full size.

the truth table of the 4027 is the following:

Click the image to open in full size.

when turned on, Q is high and the "off led" is on - fine and ok.

when i push the button, Q/ is high and the "on led" gets on and the relais closes - fine and ok, too.

this state should last until i push the button again, but as soon as i put my fingers off the button, Q/ gets low, Q high and i can see the "off led" laughing at me.


so anybody an idea, whats wrong with the circuit? i changed already the 10uF cap at clk and put a smaller one in - 0,22uF - but without any result, all the same.

thanks for help

so long
turner
  Reply With Quote
Old 11th February 2007, 07:39 PM   #2
diyAudio Member
 
Join Date: Nov 2003
Location: Louisiana
Have you tried adding a capacitor across B+ and ground?

Have you tried grounding the reset pin?

This is a circuit I built for someone. If you have a CD4013B, you may want to try it. You have virtually all of the other parts you'll need.

http://www.bcae1.com/opamptemp/flipflop01.swf
  Reply With Quote
Old 11th February 2007, 09:06 PM   #3
turner is offline turner  Germany
diyAudio Member
 
Join Date: Jun 2006
Hi,

what do you mean with B+? reset is low, this shouldn't be the problem i guess ...

so long
Turner
  Reply With Quote
Old 11th February 2007, 09:15 PM   #4
diyAudio Member
 
Join Date: Nov 2003
Location: Louisiana
B+ = 12v

I was concerned that the reset line may be picking up some noise from the B+ line. This could cause it to reset.

Does the circuit work properly if you remove the relay? Replace the relay with a 1k ohm resistor to see if the relay is causing the problem.

Are you 100% sure that the IC is in good working order?
  Reply With Quote
Old 11th February 2007, 09:34 PM   #5
diyAudio Member
 
I_Forgot's Avatar
 
Join Date: Jan 2005
Location: Phoenix, Az.
You are assuming that the switch behaves perfectly, opening and closing without any bounce. That's the problem with this type of simple circuit.

When you open or close a switch the contacts bounce for a few ms. That is plenty of time for the circuit to switch.

Have a look at some of the circuits here:
http://ourworld.compuserve.com/homep...wden/page9.htm

The 555 timer based circuits should work more reliably...

I_F
  Reply With Quote
Old 14th February 2007, 11:30 PM   #6
cpemma is offline cpemma  United Kingdom
diyAudio Member
 
Join Date: Jul 2003
Location: S Yorkshire OK
Quote:
Originally posted by I_Forgot
You are assuming that the switch behaves perfectly, opening and closing without any bounce. That's the problem with this type of simple circuit.
Some tried & tested bounce-free circuits.

The Winfield Hill one is cheap and simple (and with that provenance...)
  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
My scope doesn't work - need help! Giaime Equipment & Tools 17 23rd September 2011 06:47 AM
Help-Car deck Doesn't work jatminder Car Audio 2 10th July 2006 08:13 AM
Right Channel on my amp doesn't work?? nicku1302 Solid State 2 29th November 2005 03:58 PM
adcom gfa 545 II doesn't work Mattyo5 Solid State 1 14th February 2004 12:39 AM


New To Site? Need Help?

All times are GMT. The time now is 01:56 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