When you submit this form, the server will work out the values of t1 and t2.

For reliable operation Ra must not be less than 5K, and Rb must not be less than 3K.

Ra and Rb combined must not be greater than 10M.

Values outside this range will be shown in red.

The server will also work out the frequency and duty cycle of the output.

If both t1 and t2 >= 0.1s and both t1 and t2 <= 60s then the server will generate an animated gif showing the output flash rate.