Hi all,
In chapter 5 of Make: Electronics (experiment with 555 timer and high/low pass filters) the author says the Ac to Dc adapter might introduce some hum. He writes you can reduce it somewhat by putting a 1000 uF capacitor between Vcc and ground.
I understand the capacitive reactance is small for high frequencies and therefore those interfering frequencies (probably any non DC?) will be shorted to ground and no longer cause hum in the speaker. I wonder however why this shorting to ground is not a problem. In the end those frequencies are electricity as well and creating a short sounds like something you wouldn't want. Is it because those frequencies are "low energy" and therfore harmless?
Where will their voltage be dropped? Across the internal battery resistance?
Many thanks,
Dirk
In chapter 5 of Make: Electronics (experiment with 555 timer and high/low pass filters) the author says the Ac to Dc adapter might introduce some hum. He writes you can reduce it somewhat by putting a 1000 uF capacitor between Vcc and ground.
I understand the capacitive reactance is small for high frequencies and therefore those interfering frequencies (probably any non DC?) will be shorted to ground and no longer cause hum in the speaker. I wonder however why this shorting to ground is not a problem. In the end those frequencies are electricity as well and creating a short sounds like something you wouldn't want. Is it because those frequencies are "low energy" and therfore harmless?
Where will their voltage be dropped? Across the internal battery resistance?
Many thanks,
Dirk