Ok hope this is the correct area for this post if not please let me know as I am new to the group.
I need both a 12 and 5 volt power supply. No problem, have built these using regulators like the 78l12 and 05. But here space is very short so I want to use just one transformer.
Reading some theory it stated that it is good practice to keep the input to these regulators only 2-3 volts above what is need to help stop the heat build up. Sounds good so far.
Now I have 9-0 0-9 transformer I can use, which will give me 18 volts if I join the two windings. This I feel should be ok for the 12 volt, ok still some 6 volts too high but hopefully ok; but very high for the 5 volt supply as it will be 13 volts higher.
Now my thinking here is to use the 18 volt but also tap just one of the coils for 9 volt helping the heat build up in both circuits.
Can this be done or will I make problems as I have joined the two windings for the higher voltage?
Many thanks for any help you can offer.
vlk
I need both a 12 and 5 volt power supply. No problem, have built these using regulators like the 78l12 and 05. But here space is very short so I want to use just one transformer.
Reading some theory it stated that it is good practice to keep the input to these regulators only 2-3 volts above what is need to help stop the heat build up. Sounds good so far.
Now I have 9-0 0-9 transformer I can use, which will give me 18 volts if I join the two windings. This I feel should be ok for the 12 volt, ok still some 6 volts too high but hopefully ok; but very high for the 5 volt supply as it will be 13 volts higher.
Now my thinking here is to use the 18 volt but also tap just one of the coils for 9 volt helping the heat build up in both circuits.
Can this be done or will I make problems as I have joined the two windings for the higher voltage?
Many thanks for any help you can offer.
vlk