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• #9168
LectronFan
Moderator

Hi all,

We will do a few experiments with the Schmitt trigger module.
The first one is the charging time of a capcitor.
Since the module is very compact, it is perfect for bigger setups.

Did you know there’s a formula to calculate the time a capacitor ?

It is Τ=R*C where Τ (Tau) is the time, R the resistor value and C the capacitor value.
Τ is calculated for the capacitor to reach about 63% of the voltage applied to it.

So, for our example, T would be 10 sec.
Our Schmitt trigger reacts to a much lower voltage than the 63% of our battery voltage.
Do you know why ?
Do you think the capacitor can charge up to the battery voltage ?
Can you find a solution to set the Schmitt trigger threshold voltage ?
For the answers, check the previous experiments to find out by looking at the diagram.

If you measure the time after pressing the switch till the lamp goes on, can you determine the Schmitt trigger turn on voltage ?

Another idea is to use our Lectron modules.

Add a Emitter follower at the input of the Schmitt trigger. Add the Lectron meter with a 100K serial resistor to this Emitter follower.

Than you can measure the voltage of the threshold of the Schmitt trigger.

Many greetings • This topic was modified 1 year, 9 months ago by LectronFan.
• This topic was modified 1 year, 9 months ago by LectronFan. Reason: Added some questions and timing formula
• This topic was modified 1 year, 9 months ago by LectronFan.
• #9176
Michael
Keymaster

Innovative use of ST module Frank, well done!