Resistance/voltage testing - idiot questions...

[pplater]

Greetings comrades!

Apologies in advance for idiot questions from a raw newbie.

I have just completed construction of the ‘Crack’ and have absolutely loved the experience. The manual is next level; it’s impossible (or unforgivable) to go wrong with such marvellous reference materials. I have hit a roadblock at final testing, though (p.47): suddenly the language is foreign, and there are no pretty pictures as a safety net. What is a ‘ground buss’, for example? ‘Terminal’? Oh, if only there were pictures of where to stick the black probe and where to stick the red one! Wait: maybe there are. Is there an idiot-proof walk-through, or YouTube video, which might show a newbie how to clear the final testing? Thanks in advance.

Cheers,
pplater.

 

[Deke609]

No idea whether there's a suitable video somewhere -- but "terminal" just means the solder tabs that you labelled at the beginning of the build -- e.g., "12U" is the UPPER (U) lug labelled "12".  The reference to "ground bus" is just some descriptive language to let those interested know what part of the circuit they're attaching the clip lead to -- in this case, the 0V, aka "ground", reference black wiring.  You can ignore that language and just focus on the terminal numbers.

The first thing to do is to set up your meter.  Black lead/probe plugs into a meter socket that is usually labelled "COM" and is usually black.  For resistance and voltage testing (which is what you'll be doing), the red lead/probe plugs into the socket that's usually labelled with "V" and an Ohms symbol (Greek letter Omega).  Then set your meter to what you intend to measure: volts or ohms.  In the case of volts, you need to pay attention to whether the manual says to measure DC volts (symbolized with parallel lines, one solid, the other dashed) or AC volts (wavy line).  And if your meter is not "auto-ranging", you'll need to select the measurement range  -- e.g, mV (milliVolts) or V (Volts).  To set the range, look at the target/expected measurement value listed in the manual and then set the meter for the next highest measurement level.  For example, if you were looking to measure 80V, you;d choose the closest higher value on your meter -- e.g., "200V".  Ditto for Ohms.  But if your meter is auto-ranging, you don't need to worry about this.

For doing the actual measurements, the idea is to clip the black lead/probe from your meter to the top metal lug of terminal 12, making sure that the metal contact of the lead/probe  is not touching the adjacent terminals.  Stick one hand in your pocket or sit on it (this is really only necessary for voltage measurements -- but it's a good idea to always do this to get into the habit of safe measurement).  Then, using your free hand to hold the red probe, touch the red probe to the terminal specified in the manual and look at the reading on your meter.  It's a good idea to set the meter up somewhere that enables you to keep an eye on both the terminal you are reading and the meter screen.

Hope that helps, Derek

 

[pplater]

Yeragod, Derek! Thanks so much for the speedy (and idiot-proof) reply.

Cheers,
pplater.