SSR01 12V too low voltage

[alexanderbax]

I have built the 12V with an LM329.  I am powering it from a 15VAC transformer secondary, rectified to approx 21.5VDC.  However, the SSR01 is measuring a very steady 9.53VDC between its outputs, thats a massive drop and is a full 2.5volts below my desired 12VDC output.

Is there something I can do (resistor change etc) to bring the voltage up a little, or does this indicate I have a bigger problem?

Thanks!

Alex

[peranders]

Do you have any tin drops on J1 and J2 (solder side)?

Can you measure the voltages on the opamp, pin 2, 3, 6 and 7?

[alexanderbax]

Hi Peranders,

Sorry for the late reply, only just had time to go back to this project!

Ok, so J1 and J2 DO have tin drops on.

For the AD825:

Pin 2 = 5.49V
3 = 2.58V
6 = 2.67V
7 = 9.21V

Just a side note, I have only tested with a multimeter directly on the regulator ie. with no load attached.  Would I need to attach some kind of load to it like a resistor to get it to draw the right voltage for testing?

Thanks

[alexanderbax]

Hmmmm and now I have the opposite problem on a 5V reg I just built and tested.

This time, I am using a 9VAC secondary rectified to approximately 10.5VDC.  This is giving me 7.48Vout instead of 5V!!!!  So my 12V board drops from 21.5Vin to 9.5Vout but my 5V board only drops from 10.5Vin to 7.5Vout?

Also neither LED is lit up on the 5V regulator, despite getting 7.48Vout.

Im totally lost!! haha

[peranders]

Have you the LM329 according to the thin outline?

When the LM329 works properly you should have around 7 volt at pin 3 of the opamp.

[alexanderbax]

Ok well that's strange, I have the LM329 the correct way round and the legs are in proper position.  I'm not using a trimpot..... would it be worth adding one to try adjusting to the correct voltage?

[alexanderbax]

GOT IT (well for the 12V anyway)

My apologies, I HAD got the LM329 in the wrong slot!  Now I get a nice 12.3Vout :)

However, for the 5V I have retested it and have 12Vin and 9.5Vout (so different from earlier).  Neither LED is lighting up?

[peranders]

Check once again both the schematic and the BOM. What about the voltages around the opamp?

Have you replaced the zener by a LED and turned it right? See the schematics.

[alexanderbax]

Peranders, thanks for all your help and creating a fantastic product. I had DZ1 in the wrong way round!!! Doh!!

So both incidents were silly mistakes of mine. All fixed now and getting 12.3vout and 4.98vout  :-D :-D :-D

[peranders]

Glad to hear that you have succeeded.