Chronotron Millisecond Meter 25A : 25B : 25C

The Chronotron

A direct reading electronic stop clock for general-purpose timing in the millisecond region.

Used for timing relays and fuses; speeds of vehicles and projectiles; testing camera shutters and physiological investigations.
Timing can be controlled by contacts, by a photocell, or by externally generated voltages.

Available in three Models;

Model 25A: 0 - 4 milliseconds to 0 - 1 second in six ranges.
Model 25B: 0 - 40 milliseconds to 0 -10 seconds in six ranges.
Model 25C: 0 - 40 microseconds to 0 -10 milliseconds in six ranges.

In questo link sono elencati 7 modelli, di cui 7 con immagini e 3 con schemi.
Elenco delle radio e altri apparecchi della MicOvac (Brand) Electronic Instruments Ltd.; Richmond