Explorer for all ranges (T1098E)

This circuit was found in a Radio Craft from October 1946. Power supply not shown, and tubes are 1.5V filament types.

DM31D0UI 5-Range Voltmeter (CB24783E)
This circuit uses a digital module from the time. We found it in February 1984 Radio Electronics...
Bistable Neon (CB10505E)
I found this circuit in a Popular Electronics from November 1999. The magazine is no longer...
DC to DC converter (CB8749E)
Found in a 90s 303 Circuits, this circuit has an output power of 100 mW. L1 consists of 890 turns...