Still rummaging on the Internet, I found this function generator kit to pair with my DSO 138.

It's also a gadget, but it's a DIY kit, and I like DIY kits !

Kit assembly

The kit consists of the printed circuit board, the set of components and the enclosure, as well as the assembly instructions and the diagram. The components are few, and nothing is missing. No difficulty climbing. The waveform, as well as the frequency range, are selectable by jumpers, not very practical.

XR2206 IC

The kit is based on a specialized circuit XR2206, function generator. These circuits supplied with small kits are often copies of circuits from major brands, and have the reputation of lacking stability. It's not systematic, but I decide to buy a "real" XR2206 from RS.

Enclosure

The case is made of snap-on acrylic. Nothing special to say about it. Another gadget, but it's always a pleasure to mount these kits !!