If your fountain pen isn't writing well and you'd like help diagnosing the issue a good nib picture is essential. To start with, here's a bad nib picture. Not only is it too far away the angle isn't good enough to see the tipping as it contacts the page I'd try and not hold the pen in your hand, get some blu tack and stick the pen in there. It helps if you do this on a light coloured desk for added contrast in the image but some paper in the background works well too. Make sure you have plenty of light and turn on the flash on your phone camera too. Now we're getting somewhere. You want to take a picture looking across the tipping to see how it contacts the paper, you'll almost always want to use the macro mode on your camera for this. Here are two pictures showing the correct angle, one with macro more and one without With Macro Without Macro And finally, an image straight down the nib will show if it's seated on the feed correctly, again use mac...
Ever on the lookout for new test gear to add to my collection I stumbled across the XR2206-based function generator. These can be bought as a kit pretty cheaply from AliExpress or from eBay, they're easy to put together and use offering 1Hz - 1MHz of range through the use of some jumpers. It has two output terminals, one that gives a square wave and one that gives either a triangle or sine wave, depending on the position of a jumper. The heart of the device is an XR2206 which is an "obsolete" function generator chip with some pretty good specs and a low external parts count. I bought one of these kits because my ultra low THD sine generator (a Wien Bridge oscillator with a bulb) is fixed at ~1kHz and being able to steep the frequency (and use other waveforms) is a huge help in analysing a circuit My Ultra Low THD Oscillator After building the kit I fired up Arta to measure the THD, the results were... disappointing, 2.7% if you set the amplitude right but around 4-5% m...