Operating power from telephone line pull
Actually, it is prohibited from operating current is "stealing" from a telephone line, let alone hang out for homemade or partially homemade telecommunications equipment to the telephone line. Because it upsets me but somehow animal that one of my phones, an additional power supply of 3 AA batteries (4.5 V so) and need this phone to a PBX system and thus depends on MY system, not the Telekom provides the power, I have here tinkered a voltage regulator, with whom I get the operating current from the telephone line.
Preliminary consideration: the tension between an analog telephone line fluctuates = 60V DC ~ 25V at rest and ringing alternating with 25Hz. Most of the (fixed) voltage regulator but have a maximum input voltage of 48V. After a long search I have found a variable voltage regulator that is clearly up to 125V at 700mA. Variable means that I can even regulate the output voltage with a potentiometer, depending on what consumers want my.
The circuit is quite simple. First, a rectifier, so we only do it to others of a similar tension. To smooth then an average capacitor to the voltage and finally our voltage regulator TL-783rd Altogether this is so small that it really should easily accommodate any phone in case. Before installation, I would make the adjustment on the pot for the required voltage, but only with a voltmeter and without load.
Bill:
- TL 783 positive voltage regulator, variable
- 100V rectifier diodes or 4 as shown in diagram
- Elko 100V, 100uF
- Elko 35V, 10μF
- Potentiometer 8kΩ
- 82kΩ resistor
2 Comments
First
Vincent wrote on May 06 December 2011 00:19
interesting ... and has since worked out? I had to tap sometimes the idea of the power, but have heard quite a few warnings that the telecom is probably very quickly noticed, because the power consumption is monitored by computers. are certainly worse, Weil is prohibited because rumzubasteln turn.
but that would be potential there. and a fuse that knocked out in the telecom not to my knowledge
important for everyone with an ISDN line: better be careful here, instead of the 60 volts to 100 volts on it ... is unhealthy.
Second
Nico wrote on 13 December 2011 at 11:17
Yeah, sure it worked, otherwise I would not describe it here. The legal framework for it and the provisions of the Telecom I have not even concealed. But since I own my power from the PBX system Zapfe, I think this is my use of this power consumption is reasonable and therefore also noticed anywhere. The circuit is also not designed for high currents. Your vacuum cleaner with 800 watts I would not run it so. The power is already limited by the voltage regulator 700mA. More should not divert from the real line, but it is not built. This guide is only for analog lines, or for the front-splitter. I have no experience with ISDN and also doubt that there does this circuit without modification.