Triad VPT30-1670 into dc power supply!

Hey guys! just picked up a triad VPT30-1670 toroid type transformer which steps down the voltage to 15 volts.

I need to power up some op amps such as AD620 for my ecg im building.

I know you have to use a bridge rectifier circuit just wondering what componets i should build with and how to set up the transformer (never done before) !

Thank you,
Mark

well, you need rectifier. normally that would be bridge rectifier. if you would like to use it for powering electronics you need to filter it. this is done by large capacitor (electrolytic). optionally this would be regulated to a stable voltage. as the name suggests unregulated power supply does not have constant voltage if for example load changes.
diodes or bridge rectifier should be rated for current your circuit will draw and the transformer is rated for.
after full bridge you will get 15V * 1.41 -2*0.8 = 19.6VDC
so your capacitor should be rated at least 25V (16, 25, 35, 40, 50V are some of standard ratings).
for value of capacitors you can use rule of thumb, about 2000uF per amp. (standard values are 1000, 2200,3300,4700,5600 etc).

okay so i did some more research and found out some stuff. i will have to use voltage regulators to help me get the voltage and a negative voltage regulator.
UA78H05 for a 5 volt regulator and a IP79051H for a negative 5 volt regulator. And some 10uF at 25V caps.
Now im just wondering how to connect the actual transformer to the bridge rectifier and what kind of chip rectifier i should get instead of using diodes.

View attachment 67402

here is the schematic. just wondering what leads would go into what side of the rectifier and how to finish the circuit with the voltage regulators.

Bridge rectifiers are usually marked with ~ for each of the two AC inputs, and a + and - for the DC outputs. Connect the red and orange wires of your transformer together to give you a centre tap you can use for the zero volts line if you are making a split supply (which it looks like you are), and this then becomes the "ground" for all the stuff on the DC side like your regulators, smoothing caps and anything else you put in there - it's all either positive relative to ground or negative relative to ground. Connect the black and yellow wires to the ~ inputs on the bridge and you should be set.

Panic mode has posted some good rules about filtering - but read the data sheets for the specific regulators you will be using to find out more exact details, for example, they may recommend a ceramic cap connected to the output somewhere.

Make sure you put filter caps both before and after the regulators.

If you are not making a split supply, (ie, you're making a single supply) you still need to connect the red and orange wires together, just don't connect them anywhere else (that is, to get the voltage of both windings in series.) In this case it's usual to use the negative DC output from the bridge as "ground". If you only need the voltage of one winding, you can connect them in parallel - that would be black to orange and red to yellow - oh, but I see it says that on the datasheet anyway.

Just re-reading the thread - it looks like you expect to be dropping about 14 volts across each regulator. You should be careful about how much current the supply will be supplying - amps x volts = watts. I don't know offhand what the wattage limits are for these regulators, but you are going to need some serious heatsinks if the current you draw is in the hundreds of milliamps and up. At 1 amp you'd be looking at about 14 watts, which is HOT.

Suggest you read this thread/watch the videos. It's very good.
https://www.electro-tech-online.com/threads/power-supply-design-for-beginners.113613/

HTH.