Hello all,
I am familiar with bypass capacitors in supplies in series to GND. There are a couple of designs that use them in series to a component such as piezo buzzer or maybe to input pins of an arduino.
What is the advantage of having a ceramic or similar capacitor in series to an I/O pin ?
anishkgt:
Hello all,
I am familiar with bypass capacitors in supplies in series to GND. There are a couple of designs that use them in series to a component such as piezo buzzer or maybe to input pins of an arduino.What is the advantage of having a ceramic or similar capacitor in series to an I/O pin ?
You have the advantage of being able to see the designs you write about, but we can't. So, can you please make us all equal by posting the designs you refer to?
Paul
Sorry i was just revering in general.
here is just one of them that i found over the internet.
In that schematic the cap (C4) is there to pass an AC signal while blocking DC.
not sure what its for. The buzzer should be powered via a dc signal. I thought the others components were something to do with time constant.
anishkgt:
not sure what its for. The buzzer should be powered via a dc signal. I thought the others components were something to do with time constant.
Look at the schematic! The buzzer is supplied with DC!!!
Paul
It is not entirely obvious what that circuit is for, but essentially, it amplifies the Arduino output generating a tone (that is, an alternating on-and-off signal) to drive a loudspeaker - not a buzzer.
It has a bit of cleverness - when the tone stops, the current to the loudspeaker is cut off whether the input stops HIGH or LOW, preventing the loudspeaker being accidentally connected to continuous DC and possibly overheated.
here is just one of them that i found over the internet.
What is the circuit supposed to do?
Why would you assume that something you "found over the internet" is correct?
anishkgt:
Hello all,
I am familiar with bypass capacitors in supplies in series to GND. There are a couple of designs that use them in series to a component such as piezo buzzer or maybe to input pins of an arduino.What is the advantage of having a ceramic or similar capacitor in series to an I/O pin ?
Normally a capacitor in series with an input pin would be a mistake. However if the incoming signal is AC and
has a high enough amplitude (5V peak-to-peak basically), then the protection diodes will centre that signal
downstream of the capacitor and the voltage on the pin will be well defined. Generally an input
pin needs a defined DC voltage (otherwise its floating).
On an output pin no issue - you can adjust or remove DC offsets this way.