OverLoad
High On Solder Fumes
I was asked in this thread about the wiring and to show the inside of my DBT. So for tsd71 and other's benefit wanting to build my compact DBT version, I'll discuss it here. Pictured below is the DBT in question followed by the schematic. Also pictured is a quick mock-up I made rather than pulling mine apart so you can physically see how it's all connected. In the pictured mock-up, the black wire is the "hot" path, the white is "neutral" (depicted blue in the schematic) and the green/bare wire is ground. The longer slots on the outlet are the neutral side. In this case the 3 prong plug and cord are standard black, white and green colour coded. I've seen other cord colour coding such as brown, blue and yellow for example. Regardless, it is easy to determine with a continuity check what wires are hot, neutral and ground by knowing the longer slot of an outlet is neutral, the other slot is hot, the middle is ground and that a 3 prong plug can only be inserted the one way.
The hot wire of the plug-in cord goes to the bottom screw of the switch (off position). A wire form the top screw of the switch (on position) goes to the hot side of the top outlet (which has been isolated from the bottom outlet by breaking the tab). A wire from the neutral side of the top outlet (which has been isolated from the bottom outlet by breaking the tab) goes to the hot side of the bottom outlet. The neutral wire of the plug-in cord goes to the neutral side of the bottom plug-in. The ground wire of the plug-in cord ties to the outlet ground screw and the metal electrical box if applicable. The top outlet is where you insert the plug-in socket lamp and the bottom outlet is for your device under test.
The schematic and pictured mock-up obviously don't show the 2 gang metal electrical box that houses the duplex outlet and switch. If you use a metal electrical box as I have, then make sure the box gets grounded as well.
I've seen people building these using only a 2 prong plug and worse yet, without polarization :nono:
It's of course fine if your electrical is the older 2 wire outlets (use a polarized plug if you can) but if your electrical is present day Canadian and American code then I can't stress enough that a 3 prong grounded plug and cord be used with grounding and proper polarity strictly followed. In simplicity the DBT is an extension of the wall outlet mains but with a bulb in series on the hot side so wire it PROPERLY and SAFE! :thmbsp:
The hot wire of the plug-in cord goes to the bottom screw of the switch (off position). A wire form the top screw of the switch (on position) goes to the hot side of the top outlet (which has been isolated from the bottom outlet by breaking the tab). A wire from the neutral side of the top outlet (which has been isolated from the bottom outlet by breaking the tab) goes to the hot side of the bottom outlet. The neutral wire of the plug-in cord goes to the neutral side of the bottom plug-in. The ground wire of the plug-in cord ties to the outlet ground screw and the metal electrical box if applicable. The top outlet is where you insert the plug-in socket lamp and the bottom outlet is for your device under test.
The schematic and pictured mock-up obviously don't show the 2 gang metal electrical box that houses the duplex outlet and switch. If you use a metal electrical box as I have, then make sure the box gets grounded as well.
I've seen people building these using only a 2 prong plug and worse yet, without polarization :nono:
It's of course fine if your electrical is the older 2 wire outlets (use a polarized plug if you can) but if your electrical is present day Canadian and American code then I can't stress enough that a 3 prong grounded plug and cord be used with grounding and proper polarity strictly followed. In simplicity the DBT is an extension of the wall outlet mains but with a bulb in series on the hot side so wire it PROPERLY and SAFE! :thmbsp: