Hey everyone,
Just thought that I would do a new mini-tutorial thread for the DIY Pedals section, so here we go.....
Most of the time, when we are building our DIY pedals, and we end-up having to do some trouble-shooting to get our pedals working properly, we can usually get by with a multimeter, and our deductive reasoning, to sort things out.
But, occasionally we might come across a fault in our pedal builds where we need some way of seeing how our pedals are behaving electrically so we can narrow-down where the fault is most likely to be, this is where a piece of test equipment called an Oscilloscope comes in handy, because it gives us a way to see how an electronic circuit is actually behaving, by drawing a graph on a cathode-ray screen, or an LCD screen if you're lucky enough to own a more modern Oscilloscope.
To start with, here's a pic I took of the front-panel of my old DSE Q-1804 20Mhz Dual-Trace Oscilloscope, I have had this Oscilloscope since about 1998, or so:
Here's a close-up pic of the Oscilloscope's controls:
It's actually not as intimidating as it looks....
Starting at the top row, and going from left to right....
Intensity.....This controls how bright the display is.
Focus...This is used to focus the trace to a thin line across the cathode-ray screen.
Trigger Level....This control is used to adjust the triggering-level so that you can get a stable display on the screen.
Coupling....This controls the trigger coupling, most of the time I usually have it set to either Normal, or Auto.
Source....This controls where the Oscilloscope gets it's trigger signal from...Ch-A, Ch-B, Line, or External.
Holdoff....This control is used to help stabilize the display.
Mode....This control is used to put the Oscilloscope into different modes....Main, Mix, Delay, and X/Y.
Position.....This control is used to position the display horizontally left or right, if you pull the knob, that puts it into X10 magnification mode.
Next row of controls.....
Power On and Illumination...This is pretty self-explanatory, turns the Scope on or off, there's also an illumination function that illuminates the grid markings (called graticules) on the screen, very handy in low lighting.
Ch-A Position....This control shifts the Ch-A Trace vertically up and down, it also engages an alternate trigger function when the knob is pulled.
Ch-B Position.....Same as for Ch-A except that it controls the positioning of the Ch-B trace, does not have the alternate trigger function.
Delay Time Position....Controls the position of the delayed Trace.
Delay Time/Div.....Controls the delay time per division sensitivity.
Next row of controls...
Ch-A Coupling....This controls the Ch-A coupling....AC, Gnd (Ground), DC.
Ch-A Volts/Div......This controls the sensitivity of Ch-A.
Vertical Mode....This controls the vertical mode of the Scope.....Ch-A, Ch-B/X-Y, Dual, and Add.
Ch-B Volts/Div....Same as for Ch-A, but for Ch-B.
Ch-B coupling....Same as for Ch-A.
Ext. Trigger.....This is an external input for a trigger signal, useful for when doing frequency response tests of a circuit.
Bottom row.....
Ch-A Input....Self-explanatory.
Component Test....This can be used to test some electronic components, like resistors, caps, diodes, and transistors.
Gnd.....This is a simple grounding-point.
Cal/Beam Find.....The Cal terminal puts-out a 2Vpp Square Wave signal that is used to calibrate Oscilloscope probes that are switched to X10......Beam Find is used to find where the trace is if it is off-screen.
Ch-B Input....Self-explanatory.
Main Time/Div.....This sets the main Timebase for the onscreen display, each horizontal cm graticule corresponds to the Main Time/Div. setting.
More to come, so stay tuned.....