In the review of the theory, the following is a rule-of-thumb for selecting C and R values for clamps.
The RC time constant to fully charge the capacitor is 5RC (five times R times C). This value is equal to 1/4 of the period of the source (1/4F) (F = Frequency).
To make this design work, the fully charged event needs to be at least (minimum) 10 times this value. In short (equation):
1. 5RC > 10 * 4F
10 * 4F
Where T = RC.
Solving this for worst-case time constant:
1. T > (at least 10 to 60 times larger is preferred) 2F
Which leads to (assuming we know either R or C):
1. <d 2FC
or
1
C > 2FR
The best case is to set either R or C and determine the unknown component.
Note: if R gets too large (much larger than 60 times), the current will be essentially zero.
Question: Assuming we set R to 10K (from 100K) in step 1, what value of capacitor is needed to produce the same output in our design? (assume we used a 56 times larger factor in our design)
Assuming we set C to 1 uF (from 4.7 uF) in step 1, what value of capacitor is needed to produce the same output in our design? (assume we used a 56 times larger factor in our design)