The electronic tanpura is an Indian instrument used as an accompaniment in music practice and performances.

Origin: 1979, India. First invented by G Raj Narayan.

Description: box with buttons or dials to control tone, volume, pitch, scale.

Usage/History: Used to provide a drone sound, substitute for a live tanpura in practice and performances.

Related instruments:
Overlaps with electronic shruti box (but shruti box usually plays single chord rather than series of plucked strings)

Tanpura (https://musicbrainz.org/instrument/a19ae157-702a-40c6-892f-9bcb97328b7b)

References:
https://www.milapfest.com/instruments-india/explore-instruments/the-e-tanpura/
http://lite.mayyam.com/indcmusic/10042.02.06.00.html
Image links:
https://tabla.org/electronic-instruments/electronic-tanpura