Denshi Sentai Denziman (1980)

It's successor and the most well known Super Sentai thanks to it's american adaptation Mighty Morphin Power Rangers and the original first Super Sentai Series Himitsu Sentai Goranger.

It's the very first Super Sentai series what made many of it's successors possible. If you want to watch the original first season of the Super Sentai series.

It's the 3rd sequel of the series from Super Sentai right after Battle Fever J which is the 2nd sequel. If you would like to watch the super sentai series chronologically.

It's the 4th sequel of the series from Super Sentai right after Denshi Sentai Denziman which is the 3rd sequel. If you would like to watch the super sentai series chronologically.

Both have the main heros using electric powers and have their villian group fall due to infighting among themselves

The movie version of Denshi Sentai Denziman premiered during the Toei Manga Matsuri film festival on July 12, 1980. The character of Princess Denzi makes her first appearance in this movie and is referenced in two later episodes of the series (26, 45), placing the events of this movie sometime before Episode 26

It's the first sequel of the series from Super Sentai and the 2nd Season. Himitsu Sentai Goranger being the first prequel and first season of the Super Sentai Series. If you would like to watch the super sentai series chronologically.