You may be forced to use
Zener
regulation. And perhaps some pass transistors eh?
I too have been thwarted in my half-hearted attempt to find high voltage monolithic regulators... I am sure they exist, but I am pretty sure I don't want to search hard enough to find them, and then pay for them!
Zener regulated supplies are not that complicated. Google is your friend!
Zener
regulation. And perhaps some pass transistors eh?
I too have been thwarted in my half-hearted attempt to find high voltage monolithic regulators... I am sure they exist, but I am pretty sure I don't want to search hard enough to find them, and then pay for them!
Zener regulated supplies are not that complicated. Google is your friend!
Well, I've thought about that. A zener diode circuit is simple enough, and--theoretically--I'd need only one circuit to get to a more manageable voltage.
Voltage in through a nice power resistor (say, 5w at 10 Ohms) to a zener diode of some significant power rating (??), with voltage out tapped by some load resistance, joining the anode of the zener at ground.
Yeah. I need to learn a little more, eh?
Google is my friend? Fie! I'll work on it, and report back for those interested
Voltage in through a nice power resistor (say, 5w at 10 Ohms) to a zener diode of some significant power rating (??), with voltage out tapped by some load resistance, joining the anode of the zener at ground.
Yeah. I need to learn a little more, eh?
Google is my friend? Fie! I'll work on it, and report back for those interested
current rating or va rating how to work out
once you've worked out voltage primary secondary all that jazz how do you work out what the current the transformer is capable of delivering. Or otherwise known as it's va rating. Often i quite happilly know from salvaged transformers what the primary and the secondary is and the volatages but have no idea other than the gauge of wire which essentially gives a sort of a indication but no guarantee of what the transformer will actually produce. When a transformer goes into melt down it wouldn't do the other componentry much good i would have thought If anyone knows of a solution to working out the current rating i would love to know.
once you've worked out voltage primary secondary all that jazz how do you work out what the current the transformer is capable of delivering. Or otherwise known as it's va rating. Often i quite happilly know from salvaged transformers what the primary and the secondary is and the volatages but have no idea other than the gauge of wire which essentially gives a sort of a indication but no guarantee of what the transformer will actually produce. When a transformer goes into melt down it wouldn't do the other componentry much good i would have thought If anyone knows of a solution to working out the current rating i would love to know.
you need two out of three parts of the transformer specification.
Choose any two from Vac, Aac, VA.
You can find the third from the chosen two by using the formula P=V*A (power = Volts times Current)
But, I have to ask, why do you need the transformer AC current rating? You don't need that for DC powering requirement and you don't need it for Audio current requirement.
Choose any two from Vac, Aac, VA.
You can find the third from the chosen two by using the formula P=V*A (power = Volts times Current)
But, I have to ask, why do you need the transformer AC current rating? You don't need that for DC powering requirement and you don't need it for Audio current requirement.
re: regulators for 66V rectified
I don't know your exact requirements, but suggest another look at the LM317. To quote from the datasheet: "Since the regulator is “floating” and sees only the input-to-output differential voltage, supplies of several hundred volts can be regulated as long as the maximum input to output differential is not exceeded, i.e., avoid short-circuiting the output."
re: unknown transformer ratings
I only know of two ways to determine the power rating of a transformer. Both somewhat crude approximations. The first is the wire gauge/weight method. For the second, you apply voltage to the primary only and allow it to warm up. Then apply the maximum expected load to the secondary and measure the temperature rise. If it only has a 20-something degree rise (Celsius), the transformer will run fine in your app.
I don't know your exact requirements, but suggest another look at the LM317. To quote from the datasheet: "Since the regulator is “floating” and sees only the input-to-output differential voltage, supplies of several hundred volts can be regulated as long as the maximum input to output differential is not exceeded, i.e., avoid short-circuiting the output."
re: unknown transformer ratings
I only know of two ways to determine the power rating of a transformer. Both somewhat crude approximations. The first is the wire gauge/weight method. For the second, you apply voltage to the primary only and allow it to warm up. Then apply the maximum expected load to the secondary and measure the temperature rise. If it only has a 20-something degree rise (Celsius), the transformer will run fine in your app.
If you know the transformer's basic physical form (probably either toroidal, or E-I laminations), its mass (weight) can give you a good first approximation of VA rating. If you take it one step farther and measure the core dimensions, comparing them to detailed spec sheet or catalog drawings of transformers with known VA ratings will probably get you within a few percent of the transformer's capability.
Dale
Dale
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