Microscopy Lamp for LOMO Microscopes

One of my LOMO microscopes came with a LOMO OI-35 (ЛОМО ОИ-35) illuminator, the other just with a mirror for an external light such as theLOMO OI-19 (ЛОМО ОИ-19). So I figured to machine myself a light fixture for a 3W LED light.

Lamp fixture

I did not do any drawings for this and just figured everything out while machining it.

Machining Assembled In Microscope

I then spray painted the lamp fixture white and added a LEE diffuser filter.

Final lamp fixture


The dimmer is a straight forward current limiter, programmed to a maximum current of around 700mA. It is supplied by an external 7.5V plug pack power supply. For this reason I did not add a power switch, as dimming the lamp to zero will already put the circuit to a quiescent current that is insignificant to the standby current of the plug pack power supply.

Dimmer with opened case

Update 19.03.2023

I was getting tired of the plugpack power supply, so I added an unregulated DC supply consisting of a small 6V transformer, bridge recitifier and capacitor instead, this gives roughly the 7.5V required. I did not have a switch mode power supply in this small size factor otherwise.

I also added a cheap 4 pole connector for the fixture rather than the two Zwergbuchsen I used before. Front and backpanel are 3D printed.

New power supply