Gentlemen. Thank you for responding...
AS SHOWN BY "B" - I have 4 home built regulated power supplies. Two were recently completed with the
LM338 fed by a 4 amp 12vac transformers.. Running engines on an 0-scale model railroad, even multiple headed,
the maximun current read 1.5 amps with the Ammeter at the Vout line nearly last, just before my reversing switch.
The ammeter is as purchased and the voltmeter is connected just upstream of the Ammeter.
The maximum voltage at full throttle is read as 13 volts by the voltmeter. Applying pressure to a running 12v motor prior to stalling gave me 4 amps max. I am extremely pleased with these circuits.
AS SHOWN BY "A" - The other two home built older regulated power supplies using the
LM317 are fed by 12vac 2 amp transformers.
The ammeter was a voltmeter converted via ohm's law to read current. These power supplies
run the engines a little anemic and only draw 1 amp. The voltage max. is higher than the 13v by maybe a few additional volts. I am trying to improve the outputs of these two units to closer to the outputs of the "B" units recently completed.\
Would amp output and running improve by simply moving a real ammeter to the downstream of my "A" circuits?
I am trying to duplicate with the "A" LM317 units the
better performance of the "B" LM338 units by rebuilding, using LM338 circuitry.
According to these excellent comments, I may have 3 issues....
1 - Replace the Ohms law Ammeter with a Factory ammeter...
2 - Relocate the ammeter to downstream of the LM338, as in "B"...
3 - For both power supplies, place the voltmeter downstream and after the ammeter...
Does it look like I have properly analyzed my issues based on your good comments?
ps - The picture is the DC output of one of the LM338 regulated power supplies.