The 4700uF are 7.5mm lead spacing. 25-35V rated. 35V is better if using 15+15V transformer. (12+12V transformer allows no sinking, 15+15V is preferred against low mains regional problems or when hot rod CCS mod is planned).
The 100uF are 5mm lead spacing, 25V rated, in any case.
All BC5xx transistors in B or C hfe category are OK. C is better.
Either BC560 or BC556-9 (one of those numbers) are OK. See attachment.
You need 2X BC550, 1XBC560, 1XBC517 in total.
About the parallel resistors duet (their total value is in series with the relays rail) choice: Use 2X300R 0.5W or 2X270R 0.5W for all relays=5V (2X270R better for covering all relay brands not only NAIS).
Use jumpers for all relays=12V. Don't mix 5V and 12V relays. Use the non-latching type relays in any case.
I'm down to the last few components but need some more help. 1) Heatsink for 7812 (12V regulator) Mouser # 532-6043PB Not sold/recommended. Is there a decent mounting kit and/or clip for a TO-247 package? 2) I'm going to go with a 2x15V, 50VA Antek (AS-0515 - 50VA 15V Transformer - AnTek Products Corp) Would this be appropriate? 3) 750mA T (Slow) 115V fuse I'm really lost on this one. What is "T"? Can someone point me towards one from Mouser (and, if possible a holder?)? 4) IRFP240/9240 Heatsinking. I see plenty of pics of people using their case as a heatsink. With a standard Mezmerize build, is this OK? If not, can someone point me to a decent TO-220 kit? I have everything else ready from Mouser and Digikey and have the Jfets sourced as well. Thanks in advance for any and all help. Edit- No matter what I do, on this thread only, the formatting is off. I lay everything out neatly but it all bunches up in one lump after I submit. I don't seem to have this issue on other threads (e.g Aleph J build guide thread). What gives?
The 7812 is a typical TO-220 chip reg. Like the LM317, but fixed voltage. Any small clip on sink for those types will cater.
That Antek is alright. If 0.75A slow blow primary in line fuse is recommended for it, then:
Fuse & holder
The TO-247AC IRFP240/9240 MOSFETS will be OK sinked on the case's floor for currents about 200mA or there. Use Silpad back insulators. The bolts can be normal metal ones without extra measures since such plastic case type allows no electrical contact to the semi's tab around the top fix insert.
That Antek is alright. If 0.75A slow blow primary in line fuse is recommended for it, then:
Fuse & holder
The TO-247AC IRFP240/9240 MOSFETS will be OK sinked on the case's floor for currents about 200mA or there. Use Silpad back insulators. The bolts can be normal metal ones without extra measures since such plastic case type allows no electrical contact to the semi's tab around the top fix insert.
Thanks, Salas!
Got the fuse and holder, found this clip-on for the TO-220:
CLP-212G Aavid Thermalloy | Mouser
Mouser # 532-CLP212G
Does it just clip directly over the regulator? Do I need some sort of sil-pad? I thought it was bad having direct metal contact to the back of a device or, is it because it's floating, I won't have contact to case/ground? The Mouser catalog shows it clipped to the device and something else, just not sure what that something else is.
I didn't realize the MOSFETS were plastic-cased, which makes sense now. Thank you.
Got the fuse and holder, found this clip-on for the TO-220:
CLP-212G Aavid Thermalloy | Mouser
Mouser # 532-CLP212G
Does it just clip directly over the regulator? Do I need some sort of sil-pad? I thought it was bad having direct metal contact to the back of a device or, is it because it's floating, I won't have contact to case/ground? The Mouser catalog shows it clipped to the device and something else, just not sure what that something else is.
I didn't realize the MOSFETS were plastic-cased, which makes sense now. Thank you.
Those MOSFETS backs are exposed metal tabs. Its just their front side and eyelets are insulated.
That reg won't need insulation unless there is danger you go short from its tab/sink to chassis or PCB ground with some probe or wire. Never heard anybody saying he toasted a 7812 on a Mez or Hypno due to a short by now. Check if part # 532-534302B35 fits the space around it as it is better thermally to dissipate the power drop across it form 15V Tx rectified level to 12V when two relays are drawing from the 7812.
That reg won't need insulation unless there is danger you go short from its tab/sink to chassis or PCB ground with some probe or wire. Never heard anybody saying he toasted a 7812 on a Mez or Hypno due to a short by now. Check if part # 532-534302B35 fits the space around it as it is better thermally to dissipate the power drop across it form 15V Tx rectified level to 12V when two relays are drawing from the 7812.
The two resistors marked: NOTE 2x 600
These are intended to drop the 12V from the reg to the 5V required by a 5V relay.
I use those same resistors to drop the 15V from the reg to ~7.5V to feed my 12V relays.
This current saving saves a lot of current especially on a Mez.
But to implement it you must all fit the extra capacitor to "fire" the relay.
These are intended to drop the 12V from the reg to the 5V required by a 5V relay.
I use those same resistors to drop the 15V from the reg to ~7.5V to feed my 12V relays.
This current saving saves a lot of current especially on a Mez.
But to implement it you must all fit the extra capacitor to "fire" the relay.
That part I got.
This part is interesting. If I'm using a 2x15V transformer, but keeping all the caps the same as a standard Mez, would I need to drop the voltage with the resistors as well? Assuming I'm using the standard regulator, it would only be 12V, so I think I've answered my own question (the answer being no).
For a medium hot-rod, is it wiser to use 10R, 5W resistors like these:
http://www.mouser.com/ProductDetail/Vishay-Dale/CW00510R00JE73/?qs=sGAEpiMZZMtbXrIkmrvidDdY%2fwKIbxTCSWC3R%252bJEtlA%3d
(is 8.2R, 3W pushing it?) And, to be clear, you'd swap out the four 68R resistors for two (8.2 or) 10R resistors?
Do the MUR120 diodes need to be changed or left as is?
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Yes you forget the 68R and use one 10R/8.2R per side. 3W will do in both cases. 10R gives less than 200mA in many builds with red LEDs. When the MOSFETs aren't Vgs matched around that current, usually the negative polarity is bit weaker and the next smaller value resistor available balances it out. i.e. different resistors to offset semis tolerances. Not that it matters much for gm difference at those levels, but its nice. MUR120 can hold until 200mA with enough reliability but have them standing bit off board.
Thanks Salas. That was my next question, the MUR120 mounting. I assume something like this:
http://server.ibfriedrich.com/wiki/ibfwikien/images/8/8a/Rstehend3.png
Do you recommend teflon or heat shrinking the exposed lead?
I'm using red LEDs so I guess I'll stick with 10R (if I'm reading your right, or were you saying to use 8.2R).
If I were to use a case like those in the store, would it be safe to mount the MOSFETs to it for disippation or would they each require their own sinks, standing up? Since this is a "medium" hotrod compared to the others with 4x4700uF caps, I was unsure how hot things would get.
I'm doing my best to read all I can and ask all the questions I can think of. There are sooo many DCB1 threads here and elsewhere it's dizzying to keep track of. Thanks for answering the same questions again and again!
http://server.ibfriedrich.com/wiki/ibfwikien/images/8/8a/Rstehend3.png
Do you recommend teflon or heat shrinking the exposed lead?
I'm using red LEDs so I guess I'll stick with 10R (if I'm reading your right, or were you saying to use 8.2R).
If I were to use a case like those in the store, would it be safe to mount the MOSFETs to it for disippation or would they each require their own sinks, standing up? Since this is a "medium" hotrod compared to the others with 4x4700uF caps, I was unsure how hot things would get.
I'm doing my best to read all I can and ask all the questions I can think of. There are sooo many DCB1 threads here and elsewhere it's dizzying to keep track of. Thanks for answering the same questions again and again!
That one upright mounting is best for dissipation. If you are not going to mess with probes there and be creating short dangers better not heat-shrink cover the leads so they can radiate to air better.
With 8.2R and red LEDs the builds go closer or bit over 200mA usually with the MOSFETs and LEDS they sell these days.
Yes case mounting will suffice.
With 8.2R and red LEDs the builds go closer or bit over 200mA usually with the MOSFETs and LEDS they sell these days.
Yes case mounting will suffice.
The last thing on my build list is a 6-position switch. I have some knobs I'd like to use that are 6mm but it looks like most switches are with a 0.25" (6.35mm) shaft. Could someone verify that this part from Mouser (688-SRRN161100) is an acceptable 2-pole, 6-position selector switch?
SRRN161100 ALPS | Mouser
If I'm reading the data sheet correctly, the shaft is slightly less than 6mm so there should be some wiggle room. Also, I'm not sure what voltage rating these would need to be.
If I've made a bad choice, could someone help me find an acceptable solution (preferably from Mouser)? Many, many thanks in advance.
SRRN161100 ALPS | Mouser
If I'm reading the data sheet correctly, the shaft is slightly less than 6mm so there should be some wiggle room. Also, I'm not sure what voltage rating these would need to be.
If I've made a bad choice, could someone help me find an acceptable solution (preferably from Mouser)? Many, many thanks in advance.
Its a typical switch alright. Its role here is to just close path to ground for the selected input relay coil each time to engage. One side of the switch is to be utilized only i.e. 6 positions and their single exit. Voltage level is very low (5V or 12V) at a few mA that one relay coil draws. The other side is left idle or can be used for tricks like for switching on LEDS signifying active input position.
Thanks Andrew,
which one should I go for? Is the original a simpler build?
Is there a preference if it is being used between valve or SS?