Below is the schematic for the Velleman MK111. The kit claims the off (pause) time can be set between 2.5 to 60 seconds, while the on (pulse) time can be set between 0.5 to 5 seconds.
According to my limited knowledge and research, the following equations are used to calculate the on and off time:
ON (Pulse) Time = 0.7 x (RV2 + R1) x C3
OFF (Pause) Time = 0.7 x (RV1 + RV2) x C3
Thus,
ON_min = 0.7 x (0 + 1000) x 0.0001 = 0.07 seconds
ON_max = 0.7 x (47000 + 1000) x 0.0001 = 3.36 seconds
OFF_min = 0.7 x (0 + 1000) x 0.0001 = 0.07 seconds
OFF_max = 0.7 x (1000000 + 1000) x 0.0001 = 70 seconds
Hence, I get an ON range of 0.07 - 3.36 seconds, not 0.5 - 5 seconds and an OFF range of 0.07 - 70 seconds, not 2.5 to 60 seconds.
I'm trying to help someone else on AAC use this to get an ON and OFF time of 1 second each. The values are reasonably close, but the 2.5 second minimum pause (off) time is bugging me since it so far off from the calculated values. Am I using the wrong equations or did I put a decimal place in the wrong spot somewhere?
Any help is appreciated.
According to my limited knowledge and research, the following equations are used to calculate the on and off time:
ON (Pulse) Time = 0.7 x (RV2 + R1) x C3
OFF (Pause) Time = 0.7 x (RV1 + RV2) x C3
Thus,
ON_min = 0.7 x (0 + 1000) x 0.0001 = 0.07 seconds
ON_max = 0.7 x (47000 + 1000) x 0.0001 = 3.36 seconds
OFF_min = 0.7 x (0 + 1000) x 0.0001 = 0.07 seconds
OFF_max = 0.7 x (1000000 + 1000) x 0.0001 = 70 seconds
Hence, I get an ON range of 0.07 - 3.36 seconds, not 0.5 - 5 seconds and an OFF range of 0.07 - 70 seconds, not 2.5 to 60 seconds.
I'm trying to help someone else on AAC use this to get an ON and OFF time of 1 second each. The values are reasonably close, but the 2.5 second minimum pause (off) time is bugging me since it so far off from the calculated values. Am I using the wrong equations or did I put a decimal place in the wrong spot somewhere?
Any help is appreciated.
Attachments
-
34 KB Views: 88