Ring generator for telecom

Ring gemerators are availible, but they are not cheap. In the US you need a 20 Hz sinewave @ 90 VAC. Is this a permanent application, or temprary? A small PA amp with a 70 Volt line output and any 20 Hz oscillator woll work.

If you can find a surplus Western electric or other brand of 1A2 style key telephone power supply made for your country, it will have the right output.

has some used and surplus items, as well.

google for "ring generator"

Andre Zanon escreveu: Thanks, I will check,

This is a product we do in small quantities. Now I am using a transformer that has 2 outputs: 10V CA and 40V CA, the second one I=B4ve made a simple charge pump to generate the ring, and also the line voltage 40V CC. It is cheap this way, works well. But I am thinking about making something better, but not very expenive.

Thanks again for the info,

Andr=E9

This sounds like a job for a transformer. 5:1 step up transformer should be adequate for stepping up 12VACrms to 60VACrms. I do not know for sure, but I expect that would be adequate for ringing. You could use a 60Hz to do that, but you must remember that the primary and secondary voltage ratings are inversely proportional to operating frequency. That is, for a ringing frequency of 20Hz, the primary should be rated for 36V while the secondary should be rated at 180V.

Bill

-- Fermez le Bush

Real telephone bells require the right frequency to ring. The coil and capacitor are a series resonant circuit, and in the days of party lines, multiple users had different ring frequencies.