Breadboard help - diyAudio
Go Back   Home > Forums > Amplifiers > Tubes / Valves
Home Forums Rules Articles diyAudio Store Gallery Wiki Blogs Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Tubes / Valves All about our sweet vacuum tubes :) Threads about Musical Instrument Amps of all kinds should be in the Instruments & Amps forum

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
Thread Tools Search this Thread
Old 23rd December 2010, 03:58 PM   #1
g(f(e)) is offline g(f(e))  United States
diyAudio Member
Join Date: Dec 2007
Default Breadboard help


I have built a few chassis projects but now I want to experiment some before my next project. I have seen numerous pictures on the site of various breadboard setups, and have a few questions.

I will be using a 2 amp fused Variac for the main power to the breadboard. I want this board to be as safe as reasonable given the fact it will have many exposed wires.

Should I still have an inline fuse of some sort coming in to the power supply?
Should I still use earth ground, even though there is no chassis to ground it to? Does an isolation transformer make it safer? Any other suggestions to make the breadboard safer would be appreciated.


  Reply With Quote
Old 23rd December 2010, 07:08 PM   #2
M Gregg is offline M Gregg  England
diyAudio Member
Join Date: Jun 2010
Location: UK

You have to remember that breadboard projects are no different from a standard build. The fact that it is a bread board project means your safety should be as good or better.
Don't forget discharge resistors across HT caps in power supply.
Test before you touch!
You "must" use an isolation Tx. If you don't your fault current will be higher.
All circuits should have their own fuse, If you get a short it will limit damage done "not prevent it".
Gnds should be at Earth potential " connected to earth".
If you get a gnd fault it will rise to fault potential "Above Gnd" if you then touch gnd you will get a shock!

Any tracks on the bread board should be able to with stand currents used if it is large then "Tin " the track with solder!

For testing an in line earth leakage CB is an extra safety measure!

Don't get over confident "just because it's a bread board project" if it has HT it has potential to kill!

Be safe and have fun!

M. Gregg
  Reply With Quote
Old 23rd December 2010, 07:29 PM   #3
g(f(e)) is offline g(f(e))  United States
diyAudio Member
Join Date: Dec 2007
Thank you.
  Reply With Quote
Old 23rd December 2010, 07:41 PM   #4
M Gregg is offline M Gregg  England
diyAudio Member
Join Date: Jun 2010
Location: UK
Just for interest.

In the "early days" of tube radios it was common practice to have a 2 wire system with the chassis connected to Neutral "return" and live straight to a rectifier and circuit. The problem with no Tx between you and supply means that if you contact the live supply when touching the Gnd (" at Neutral / return" ) potential you become the circuit between the two! Or the live may be connected to gnd by mistake.

A power Tx creates a break between the mains and your circuit "you can then make a Gnd on the supply side of the circuit.

Hope this is of help.

M. Gregg
  Reply With Quote
Old 23rd December 2010, 08:38 PM   #5
diyAudio Member
Soonerorlater's Avatar
Join Date: Jul 2008
Location: Belfast
You have been a member for some time now so I suppose you'll have read the "STICKY" thread on safety, if not here it is

Brgds Bill
  Reply With Quote


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
Breadboard Class D!! nitrate Class D 218 12th September 2011 04:04 PM
IRS2092 on breadboard rob mullen Class D 31 27th November 2010 12:24 AM
Breadboard fun!! Resaebiunne Chip Amps 3 7th November 2007 07:25 PM
HELP with breadboard layout!!! AudioGeek Tubes / Valves 4 11th September 2005 08:13 PM

New To Site? Need Help?

All times are GMT. The time now is 02:50 PM.

vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright 1999-2017 diyAudio

Content Relevant URLs by vBSEO 3.3.2