Solved
You raise e to the power t, and t has a dimension (s). Any power that you raise e to MUST be dimensionless. You probably forgot to define and use the time constant (tau?) that t must be divided by in the exponent of e.
ttokoro (above) used a simple 1s for that.
And finally you defined V as an amplitude, but you don't use it, but that shouldn't present a plotting problem.
Anyway:

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Luc
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