One of the first truly electronic pianos was produced by the Wurlitzer Company in 1955 using electrostatic pick-ups and replacing the strings with steel reeds. The Wurlitzer 200A became popular in the 1960s and 70s and became an integral part of the sound for bands like Supertramp who used the Wurlitzer extensively.
Its main rival in the mid 1960s was the Fender Rhodes piano which had a softer, mellow laid-back tone and was first introduced in 1965 having been originally invented by Harold Rhodes during World War II. The Fender Rhodes went on to surpass the success of the Wurlitzer mainly because its sound adapted so well to many different types of music from Jazz to Rock to Soul and it is still used today having become a classic instrument.
Today's Digital pianos largely use sounds that have been sampled from original classic keyboard instruments such as the Wurlitzer and Fender Rhodes along with samples of Steinway and Bechstein Grand Pianos. In modern Digital pianos these sounds are available at the touch of a button and some models of digital piano even allow several sounds to be simultaneously layered and played together.