Jens, not a big problem really but I try to when it's possible to add optional parts because I don't like parts pacthed in here and there. Compare the work to fit in a LM431 if you thought of a LM329 in the first place. It's better to make a 4 pin part so both types will fit or simply have two footprints, one for the LM431 (and similar) and one for LM329 (or similar).JensRasmussen said:May I suggest soldering a resistor on the bottom side if extra trimming is needed
No point making a big problem out of nothing - IMHO
\Jens
The 431 is out of the question as the voltage divider needed for low voltage references will raise the output impedance a lot (lower loop gain) I prefer the 10V LM4040 as this allows for a voltage divider with more gain compared to the 431 (2.5V) divider
The capacitor in parallel with the emitter resistor has been removed as I found it was not needed for stability. For practical reasons I have left it out as the cap needed to actually do any difference was so big (>100uF) that I chose not to bother
Initially I wanted it to be there as a gain reducer at high frequencies…. I found it to be not needed and removed it.
\Jens
The capacitor in parallel with the emitter resistor has been removed as I found it was not needed for stability. For practical reasons I have left it out as the cap needed to actually do any difference was so big (>100uF) that I chose not to bother
Initially I wanted it to be there as a gain reducer at high frequencies…. I found it to be not needed and removed it.
\Jens
Based on the preliminary schematic, here is a BOM. At current interest, the 15V parts kit for the board (both positive and negative regulators) will cost $16 without a trimpot. Using Bournes 3296Y multi-turn pots would add about $3.62/kit
For 12V use you could add a 100K trimpot and just dial down the voltage or swap R11 and R13
I just put parts in the order that they caught my eye, sorry.
D7,9______________________________LM4040-10___National
D1,2,3,4,5,6,11,12,13,14,15,16_________1N4004_____Diodes, inc
C4,5,31,32_________________________680uf/35v___Panasonic FC
C10,12,22,24_______________________470uf/25V___Panasonic FC
C6,7,11,13,16,19,22,24_______________1uf_________EPCOS
C1,2,3,8,9,14,17,18,20,21,26,29,30,34___100nf polyester film___EPCOS
C7,28_____________________________220nf polyester film_________EPCOS
R2,7,16,18_________________________10K_________Panasonic 1%
R3,4,5,19,20,21_____________________1K__________Panasonic 1%
R11,13____________________________2K__________Panasonic 1%
R6,10,12,17________________________330_________Panasonic 1%
R9,14_____________________________100_________Panasonic 1%
R8,15_____________________________22K_________Panasonic 1%
R23,24____________________________680*________Panasonic 1%
T1________________________________MJE15033G___OnSemi
T8________________________________MJE15032G___OnSemi
R1,22_____________________________1R 2W________Vishay BC
LED1,2____________________________LTL2T3TBK4 (blue)___Lite-On
T2,5,6_____________________________BC556C______Fairchild
T3,4,7_____________________________BC546C______Fairchild
* R24 and R24 are chosen to give ~15 mA LED current and keep their dissipation down to .15W. I don't care for full brighness of the LED (~400 mcd) and if you drop the resistor to 400R to get full brighness you need a 1/2W resistor, since the dissipation will be .3W. Space is a bit too tight for a 1/2 W resistor. Comments?
Also, the LM4040-10 is the 1% version. For $.75 more per kit, why use a 5% zener? Comments welcome again.
Trimpots in the kit?
Any comments on parts selection?
For 12V use you could add a 100K trimpot and just dial down the voltage or swap R11 and R13
I just put parts in the order that they caught my eye, sorry.
D7,9______________________________LM4040-10___National
D1,2,3,4,5,6,11,12,13,14,15,16_________1N4004_____Diodes, inc
C4,5,31,32_________________________680uf/35v___Panasonic FC
C10,12,22,24_______________________470uf/25V___Panasonic FC
C6,7,11,13,16,19,22,24_______________1uf_________EPCOS
C1,2,3,8,9,14,17,18,20,21,26,29,30,34___100nf polyester film___EPCOS
C7,28_____________________________220nf polyester film_________EPCOS
R2,7,16,18_________________________10K_________Panasonic 1%
R3,4,5,19,20,21_____________________1K__________Panasonic 1%
R11,13____________________________2K__________Panasonic 1%
R6,10,12,17________________________330_________Panasonic 1%
R9,14_____________________________100_________Panasonic 1%
R8,15_____________________________22K_________Panasonic 1%
R23,24____________________________680*________Panasonic 1%
T1________________________________MJE15033G___OnSemi
T8________________________________MJE15032G___OnSemi
R1,22_____________________________1R 2W________Vishay BC
LED1,2____________________________LTL2T3TBK4 (blue)___Lite-On
T2,5,6_____________________________BC556C______Fairchild
T3,4,7_____________________________BC546C______Fairchild
* R24 and R24 are chosen to give ~15 mA LED current and keep their dissipation down to .15W. I don't care for full brighness of the LED (~400 mcd) and if you drop the resistor to 400R to get full brighness you need a 1/2W resistor, since the dissipation will be .3W. Space is a bit too tight for a 1/2 W resistor. Comments?
Also, the LM4040-10 is the 1% version. For $.75 more per kit, why use a 5% zener? Comments welcome again.
Trimpots in the kit?
Any comments on parts selection?
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