Four 10mF/25V caps added. B540 replaced with Schottky PBYR1025 in TO220 to save space - a bit hot. Vripple = 0.7mV rms @ 9.2 ohm load
Yet, there is a difference between attached schematic and tested circuit, i.e. values were measured with one LED setting reg2 voltage. Need to add another one.
Output voltage ripple. 2 mV/div @ 10,13V DC and 9,3 ohm load.
C6 has no significant effect on ripple voltage.
C6 has no significant effect on ripple voltage.
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Same condition, except rectifiers changed to Schottky 1N5822 (was PBYR1025). Darn!
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Same condition, rectifiers are Schottky SB540. See for yourself, I go back to 10A 25V PBYR1025 in TO220.
Back to PBYR1025 Schottky in voltage doubler.
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So some more testing: BY229/800.
20mV/div. Just for fun and reference.
20mV/div. Just for fun and reference.
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Back to PBYR1025. Added 2200uF || C8 (10uF).
Scale: 2mV/div
Enough. Now I can tune output current and connect a tube.
Scale: 2mV/div
Enough. Now I can tune output current and connect a tube.
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Tube 6C4C filament connected with 2200uF || C8 - oscillations. .5us/div
2200uF removed. 5 ms/div
Tube 1. Uf=6.10V so far, so good.
Tube 2. Uf=6.18V
Tube 3. Uf=6.15V
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2200uF removed. 5 ms/div
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Tube 1. Uf=6.10V so far, so good.
Tube 2. Uf=6.18V
Tube 3. Uf=6.15V
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Note 2 LEDs at left - seems they have different specs. Brightness and voltage drop are different, 1.9V and 1.6V.
what is your voltage drop across the regs? The LM317 performs best with at least 5V in to out difference 🙂 if you don't have 10V to drop then make the voltage drop on the second one higher, making sure to at least have more than the drop out voltage on the first one 🙂 (unless of course it doesn't matter in this configuration which I have not tried).
Tony.
Tony.
Voltage drop across current reg is 3.5V+1.24V across 1.22 ohm resistor+6.1V across filament equals 12.84V. So there is roughly 6V drop across TPR.
I must use heatsinks with lower C/W, I think. They are quite hot. I can touch it, but not too long. I guess they are about 50-60 C. I will try to measure temperature tomorrow.
I must use heatsinks with lower C/W, I think. They are quite hot. I can touch it, but not too long. I guess they are about 50-60 C. I will try to measure temperature tomorrow.
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Filament regulators for 6C4C completed.
Measured or shall I say estimated* temperature of heatsinks of all regs - they are 65 to 75 deg C hot in open air. I guess regs themselves has higher temp. I will measure when the board is inserted into the enclosure.
Schottky diodes are mounted without heatsinks and the temperature is about 40 deg C.
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* I used temperature sensor form the kitchen oven while my beloved wife was away 😀
Schottky diodes are mounted without heatsinks and the temperature is about 40 deg C.
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* I used temperature sensor form the kitchen oven while my beloved wife was away 😀
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Tracking pre regulator LM317, LM337 with highly denoiser.
See WEB link below.
.
Using 3-pin regulators off-piste: part 4
.
See attached ZIP files.
PCAD2006 binary files.
Gerber files for China and Taiwan.
Dimension 100x100 mm.
.
You may use LM317HV, LM337HV .
VD7, VD12 is a LED with 2.8 ... 3.2 Volts across.
.
See WEB link below.
.
Using 3-pin regulators off-piste: part 4
.
See attached ZIP files.
PCAD2006 binary files.
Gerber files for China and Taiwan.
Dimension 100x100 mm.
.
You may use LM317HV, LM337HV .
VD7, VD12 is a LED with 2.8 ... 3.2 Volts across.
.