All pictures taken with my Sony SLT-a77 with a Minolta AF 28-100mm F3.5-F5.6, Minolta AF 50mm F1.7 and Tamron SP AF 70-300 F/4-5.6 Di VC USD.
Unfortunately we got extreme sun on that day, so it was always a game of finding the right exposure compensation.
Dresden May 2023
All pictures taken with my Sony SLT-a77 with a Minolta AF 28-100mm F3.5-F5.6 and Sony DT 18-55mm F3.5-5.6 SAM objective.
Fürstenzug Dresden Zwinger Dresden Zwinger was partially closed for construction at the time of my visit.
Architecture View Japanisches Palais
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
All pictures taken with my Sony SLT-a77 with a Tamron SP AF 70-300 F/4-5.6 Di VC USD objective.
Corsac Fox Kangaroos (Or wallaby? Map and website of the Zoo are fairly non-descriptive)
Meerkats Giraffe Common Eland Antelope Storks Red Pandas Peafowls Chicken Jaguar
7W Linear LED Driver
Built another linear dimmable LED driver to retrofit into my microscopy equiptment. This one is for retrofitting my LOMO ОИ-35. It’s a fairly standard current reguator circuit working on unregulated DC. I used a 2N3054 transistor as the main series pass transistor for a change.
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. Haven’t bothered to reverse engineer the exact circuit, as the PCB can’t be removed without desoldering all the wires which I did not want to bother with at this time.
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
100μA and 50μA Reference
I recently built this small microampere reference using two LM334 current references. It is powered from a small 3V lithium button cell.
HP 3478a Standby Power Supply
A while ago I replaced the battery in my HP 3478a multimeter, this battery is in charge of keeping the calibration values inside an SRAM. Since I norally have the multimeter plugged into the wall anyhow I decided it may be a good idea to add a standby power supply such that the battery doesn’t drain that much (other than its internal resistance).
So I did. There is a 78L05M generating a 5V rail, and I also added some super capacitors for good measure that on their own will keep the SRAM supplied for >1 week without the battery. The transformer is short circuit safe.
Zoo Saarbrücken January 2023
All pictures taken with my Sony SLT-a77 with a Tamron SP AF 70-300 F/4-5.6 Di VC USD objective.
Corsac Fox Snowy Owl Eland Antelope Zebra Peafowl Penguins Cheetah Flamingos