Rating of dry reed relay for a line carrying 25-50 mA current?
The wire will be carrying a constant current of 25 - 50 mA.
I'll be using a reed relay for this switching purpose (Is there a better option?)
What i need to know is :
1> What should be the rating of the reed relay ?
2> Is contact protection essential in this situation ?
3> If it is essential, how should it be done ? using a diode or a series RC snubber ?
4> In case i' m using a diode, is a single diode 1N4007 (general purpose rectifier diode) across the relay enough ? Or should I use some other diode ?
5> In case i'm using a RC snubber, can somebody please explain how it should it be done, or post a suitable link regarding the same.(i have searched, btw, and am LOST).
6> Also if possible, can someone explain or post a link regarding the working and connection of a dry reed relay.
My project includes a landline telephone.Now, it is illegal (and may be a cause of harm to telephone company property) to connect any unauthorised device.
The wire (in my question) is acting as the phone line,(because i dont want to take chances connecting anything to the phone) which operates with a voltage of about 48V(i'll be using a much smaller voltage, may be 9V) and a current of 25-50mA.
By using pulse dialling (read here for more details:
http://en.wikipedia.org/wiki/Pulse_dialing) i.e. opening and closing a switch in series with the phone line, a number can be dialled.
For example, to "dial" number 9, the switch will have to be closed 9 times in a second.
The pulses of current so generated through the wire will be seen on an LED(simulating the outgoing telephone signal).
Do let me know the solution, or whether any more information is required.