bec sau sonerie pe firul de telefon

In principiu asa, ce mi-ar trebui ca sa pun o sonerie pe firul de telefon, sau sa conectez un bec ceva, Scopul fiind ca atunci cand suna telefonul, sa-mi pot pune inca o sonerie in alta parte, sau un bec ceva, fara sa fie necesar un alt aparat telefonic... Exista vreo piesa care sa-mi 'recunoasca' cumva atunci cand suna telefonul?...

daca este aparat clasic (cu disc) e mai simplu decat iti imaginezi.. trebuie o bobina plasata pe carcasa telefonului si un motaj... daca este aparat nou, ai putea face rost de un aparat clasic (chiar si defect) si recuperezi doar soneria ;)

deci tot trebuie sa ma folosesc de un telefon intreg... Nu exista ceva, acolo o piesa doua, un grup de piese care sa transforme semnalul dat pe firul telefonic (atunci cand telefonul suna) in contact electric... adica atunci cand suna, sa-mi faca piesa respectiva un contact prin care sa pornesc ceva (bec/sonerie) ... (Daca exista, este mai mult curiozitate...)

un releu la o tensiune mai mare de 48 V :)

When a phone line rings, there's 90 V RMS AC at 20 HZ on the line. It's enough to give you a jolt you won't soon forget. Thus, it's hard to miss!

My favorite detection scheme looks like this. This is off the top of my head so you may have to twiddle component values a bit. Also, this is for driving logic circuits. I'll treat your specific problem in a bit.

Detector Schematic


                        +-------------------------- + DC power supply
                        |
                        ^
                       CR2
                        |
O---C1--+--R3---+--CR3>-+-------+-------+-----> ring det logic
                |       |       |       |
phone           R2      ^       C2      R1
line            |      CR1      |       |
                |       |       |       |
O---------------+-------+-------+-------+----- GND

C1              .1 uf
CR1,CR2,CR3     1N914
C2              10 uF
R1              100K
R2              10K
R3              100K

Mostly, there is only DC or small signal AC (audio) on the phone line. C1 blocks the DC, and the R3-R2 voltage divider prevents the low level AC from having any effect.

When the ring signal comes along (90V RMS) enough voltage is developed at the juncture of R3 and R2 that some charge is pumped into C2 via CR3. Protective diodes CR1 and CR2 ensure that the output of this circuit will not grossly exceed the power supply levels and thus damage the logic circuits it may drive.

C2 and R1 have a time constant of 1 second, so one second after each ring ends, the output will fall to a logic zero again. This circuit could easily drive a counter, to count rings. A timer with a longer period could be used to reset the counter if no rings have come in within say 10 seconds.

For the specific problem in the post I'm answering, (" LED should stay ON while the phone rings") you would want to change the design somewhat. Here's how I would make a ring indicator light that stays on until the phone acutally stops ringing:


O---C1--+--R1---+--CR2>-+-------+--R2---+
                        |       |       |
phone                   ^       C2     LED1
line                   CR1      |       v
                        |       |       |
O-----------------------+-------+-------+

C1              1 uF, decent voltage
C2              see text
R1              10 K
CR2             1N914
CR1             zener -- 9v or higher
R2              1 K
LED1            any old LED

I haven't built this, but here's my theory: C1 blocks DC, R1 limits the current that the ring voltage could cause. The ring voltage is rectified by CR2, filtered by C2, and limited in amplitude by zener CR1. Then the charge stored in C2 is slowly used to light LED1. As long as C2 is large enough (I'd start with 10 uF and experiment from there) to keep the LED on between rings, and small enough that the LED goes off within a reasonable amount of time after the last ring, you're set.

k, mersi la OL de raspunsuri; acu tre-sa ma ocup de tradus schema :)

un pik de ajutor

si asa trebuia sa arate schema a doua

Ceva asemanator cu a doua schema...am experimentat eu si merge....

Citat

phai e normal sa mearga...doar nu postez prostii!  :cool:  :D

Looool ...am spus asemanator:)
De fapt e cu mult mai putine piese!:)

Așa, în primul rând nu râdeți de mine! :P În al 2-lea rând, vreau să fac ceva de genul: bunicii mei stau cam prost cu auzul, niciodată nu aud telefonul fix când îi sun. Vreau să știu dacă pot trage de la telefon până la ei în cameră unde stau toată ziua la tv, un fir cu un bec să înceapă să pâlpâie atunci când sună telefonul? Mulțam! :D

Sigur ca da.
Tensiunea care apare pe linie in momentul unui apel este de 70-75V, 25Hz.
Un montaj care poate fi construit este acesta: http://www.aaroncake...uits/pflash.asp

Deasemeni, parca pe la Romtelecom am vazut montaje construite pentru avertizare luminoasa/audio. Se ataseaza pe linia telefonica si fie aprind un bec, fie suna (mai tare decat o face telefonul). Merita sa tragi o fuga pana acolo, cu 20-30 Ron ai scapat de balamuc.

Mulțam de ajutor, ești singurul care-a binevoit! :cheers: