A fairly simple phase angle control dimmer using a triac, diac, resistor, potentiometer and a capacitor. For noise suppression I added an inductor and a filter capacitor.
Arduino Traffic Light Controller
Fairly simple traffic light controller I built the other day. It consists of 5x relays switched using a ULN2803 darlington array with free wheeling diodes from an Arduino. Two digital inputs are also available to hook buttons up. 12V/DC power is supplied using a 230V/AC PCB SMPS module.
Not too much to say about it really.
Teufelsburg (Saarland)
Château du Falkenstein
Dresden May 2023
Quick Repair: Tempophot
I got this old camera photometer a while back and it wasn’t working, so I figured let’s see what’s wrong with it. Turns out the photocoll just wasn’t making good contact, I rotated it slightly ~45° and the meter started working again.
The fotocell is dated 26. March 1935.
Links Tempophot - Antique and Vintage Cameras Tempophot T-4
Zoo Saarbrücken May 2023
7W Linear LED Driver
Hund FLQ75 Repairs
Circuitry Overview The circuit is super simple, there is a motor run capacitor for the AC fan which is connected to a separate tap on the transformer and insulated from the rest of the circuitry. A small triac dimmer on the secondary 12V AC side using a MAC223 triac and another 3 pin TO-92 device which I think is either another triac or a SCR two film capacitors and a couple potentiometers.
Microscopy Insights #8: Grinding Wheels
Putting some bench grinder wheels under the microscope, here is a selection. I may update this post as I get new ones or also add some older/used ones I have sitting around.
Picture Grit Type Manufacturer 36 NK Manufacturer 1 36 NK Manufacturer 2 60 NK Manufacturer 1 60 NK Manufacturer 2 60 EK Manufacturer 1 80 SC Manufacturer 1 80 SC Manufacturer 3