Hi Guys!
I am new to this forum. I am a little handy with electronics but don't know the inner workings of components etc.
I have a small little school bell timer which you can set the time to ring the bell. The problem is that the duration that it rings the bell for, is to short. It only rings for around 3 seconds and because we use this electric siren, you hardly get to hear the bell and its off again. So I needed to just keep the relay active for maybe around 8 to 10 seconds.
I have opened the unit up and found that it uses a BC547 / BC557 pair to activate the relay unit.
Is there a way for me the keep the relay active for longer by adding a Capacitor or something somewhere in the circuit?
If so, how do I do it? which pins should get the + and which should get the -.
The circuit operates on 5V dc.
Any help would be really appreciated.
Thanks alot
I am new to this forum. I am a little handy with electronics but don't know the inner workings of components etc.
I have a small little school bell timer which you can set the time to ring the bell. The problem is that the duration that it rings the bell for, is to short. It only rings for around 3 seconds and because we use this electric siren, you hardly get to hear the bell and its off again. So I needed to just keep the relay active for maybe around 8 to 10 seconds.
I have opened the unit up and found that it uses a BC547 / BC557 pair to activate the relay unit.
Is there a way for me the keep the relay active for longer by adding a Capacitor or something somewhere in the circuit?
If so, how do I do it? which pins should get the + and which should get the -.
The circuit operates on 5V dc.
Any help would be really appreciated.
Thanks alot