Home

   Technical
   Articles

FET timers….. the last chance to get your hands on a simple free flight timer for brushed motors

In December 2016 Ian offered to make a batch of timers, foc for PMFC members.

What you get is as in the picture attached but less the motor and battery. These are shown only to give an idea of how to hook the system up. The battery and motor leads are left over long so that the user can shorten to suit the installation. The spec is as below:-

The battery and motor connectors are down to the user.
All units have been power tested using a 2amp current draw.
The system is guaranteed to 2amps but might do more unguaranteed.

The timer has a fixed 210k resistor to give a run time of 12-14s from a 9v battery. You can get less if you reduce the applied voltage . If you want more solder another resistor in SERIES. The increase in run time is approximately linear with the magnitude of the resistance.

If the motor runs the wrong way change the polarity of the motor connections. Do not change the battery connections around unless you want to say hello to the smoke fairy.

Ian Middlemiss - December 2016