I am trying to get my circuit to sound a 8 ohm speaker for 5 seconds (500hz sound).
Am I right in what I've done? Can someone explain the R C calculations and setup to get 5 seconds. I am trying tio get my head around it.
Thanks.
Will one of these circuits suit such a simple application?
Its annoying me, I think I am just getting confused. I simply want to make a speaker squeal at 500 hz for 5 seconds....I hope you can help.
I think I have to set a monostable up for the time aspect (5 seconds) and an astable for the frequency. I want the circuit to be real so is this circuit right or will the speaker not work?
What values are practicle (for nonostable 5m resistor and 1microfarad cap) and astable ( 2 x 1k resistors and 1 microfarad cap)?????
You should use a monostable for the 5 second timer. Here is a value calculator: **broken link removed**
And for the tone frequency (Scroll down a little): **broken link removed**
Here are some examples of what could work for your doorbell: **broken link removed**
i am also doing the same doorbell project my speaker is continously ringing when its suppose to ring for only 5secs .what could be the problem? I have selected my monostable 100k resistor and 45micromfarad cap and astable 2.7k and 4.7 k resistors with a 0.15 micro farad cap.
not cosiure but you could just short the push button and have the doorbell button turn the power on and off.
would need another 555 to hold the power on while the doorbell rings.
look at using the 7555 = cmos version= less power.
the 555 = 10-15 ma supply current
7555 = 60-300ua supply current if I am reading the data sheet right??
at ua the unit could be powered up all the time then the timer doesn't need to reset itself every time the button is pressed.
just my opinion.