The first electric movement to bear the “ESA” name on its plates was the ESA 9150 or “Dynotron”. This was a Fixed Coil, Transistor Controlled Balance type movement and appeared in 1968; it was the worlds first movement with a balance that employed a transistor.
The Dynotron range continued through to the mid to late 1970s: ESA 9154, ESA 9157, ESA 9158…
…and then there were a few weird movements: firstly, the ESA 9156 Dynotron from 1972 looks like a normal ESA 9154 from the balance side, but turn it over, and it has a series of discs to display one’s biorhythms. It was only used in the Certina Biostar Electronic watch. Secondly, the ESA 9176 Dynotron from 1975 which consisted of a series of cylinders for the numerals, very similar to a car mile-o-meter. The balance wheel is on the end of the cylinder assembly in this movement; although it looks very strange, the working principles of the ESA 9176 are identical to the other Dynotron movements. I believe it was only ever used in the Jaz-Derby Swissonic. Thirdly, the ESA 9159 which, from the balance side, looks identical to an ESA 9158, but turn it over and you’ll see that there is no provision for conventional hands; instead it took discs and was only fitted in the Gruen Electronic jump hour watch.
More information on the different ESA Dynotron calibres can be found here
Like the Landeron-produced electric movement, you’ll rarely find “ESA” on any dials (but see the left hand link “ESA on the Dial”), but with the exception of the ESA 9159 and ESA 9176, these Dynotron movements were made in their tens of thousands and appeared in many different watches, some of which I own and are listed in the links below. Also like the Landeron, the watch manufacturers often assigned their own calibre numbers to theses ESA movements. On the 9158s, ESA even provided a recess for the watch makers own plate; you can see this in the Hamilton link below: Hamilton Cal. 683 (ESA 9154), Hamilton Cal. 702 (ESA 9158).
ESA were also very successful in the tuning fork area. They licensed the technology from Bulova in 1968 and production of the ESA 9162 (date) / ESA 9164 (day and date) tuning fork movement starts in 1969. It ends in 1976. Many watch companies employed the ESA 9162 / ESA 9164 including the ones I own below:
- Baume and Mercier Tronosonic
- Eterna Sonic
- Longines Ultronic
- Omega f300
- Tissot Tissonics
- Titus Tuning Fork
ESA also modified the 9162 by adding a chronograph plate to the movement; the resultant ESA 9210 is the only chronograph tuning fork watch ever produced; it was only produced in small numbers (21,000) and today it is highly sought after. It was used by Omega (in their Speedsonic range), Certina, Longines and a few other manufacturers.
I have a number of watches with the ESA logo on the dial. It is thought that these were either demonstration or training watches. Firstly, I bought this ESA 9150 movement to be used for parts but was surprised to see the dial when it arrived. It has the ESA logo and the word “Dynotron” on it: