Nigel Goodwin said:Really the biggest problem is finding a transformer that fits the PCB, they are usually all a little different.
But from RS Components there's a 6V 1.5VA under 347-3388, and a 15V 1.5VA under 347-3417 - they don't list a 15V 1VA (at least on the first page).
NewcastleSAR said:Hi Nigel..
Sorry about the links to RS Components. What you have quoted below is what the links I had should have pointed you towards.
Is the 347-3388 transformer suitable for this circuit?
In relation to the 220VAC/15VAC 1A transformer, the nearest I could get was the 347-3417. If this okay?
Nigel Goodwin said:You've just changed your details! - you previously said 1VA, now you're saying 1A - which is it?. The transformers I referenced were both 1.5VA.
EDIT: I've just checked the diagrams you posted, the 6V one is 1.5VA, the 15V one is 1A (15VA), so if you wnat to build that circuit you need to look for a 15VA transformer. Bear in mind, most of the RS transformers have two windings, which you should connect in parallel.
The 6V one lists a Conrad transformer, have you considered ordering that?.
Nigel Goodwin said:That ones 36VA not 15VA - it would work fine, but will be more expensive and larger than needed.
310-1342, 8V and only 1VA but it's still powerful enough for your application or preferably 347-3394, 9V, 1.5VA, it's also cheaper which is suprising.NewcastleSAR said:Hero999..
What would be your recommendations from RS components
Don't just blindly build a circuit, try to understand how it works.As it is, I'm still waiting on responses from the Guys that designed the circuits.
Hero999 said:310-1342, 8V and only 1VA but it's still powerful enough for your application or preferably 347-3394, 9V, 1.5VA, it's also cheaper which is suprising.
Don't just blindly build a circuit, try to understand how it works.
NewcastleSAR said:I can't seem to marry the 15VA and the output and 1A for this transformer to one at RS. The nearest I get to it is 347-2694 (16VA) but it only supplies 0.5A.
Google is your best bet.NewcastleSAR said:Can you recommend a good book or website location that would help me understand transformers and how to select the correct one.
VA is Volts times Amps, a 15V 15VA transformer can supply a maximum current of 1A.I'm still trying to tie in the values of the transformer in the circuit to understand the VAC (in/Out) versus the VA values and the output current it can supply.
In simplistic terms and at the risk of getting a smacked, with reference to the 220VAC/15VAC 1A transformer, is this essentially a transfomer that steps down 220 Volts AC to 15 Volts AC and can supply an output current up to 1 amp?
I can't seem to marry the 15VA and the output and 1A for this transformer to one at RS. The nearest I get to it is 347-2694 (16VA) but it only supplies 0.5A. The next one up is the 201-8738. Its supplies 0.73A but the VA has gone up to 22VA.
Transformers voltage are always specified as Root Mean Square (RMS), an AC voltage that will do the same work as a DC voltage.In the 6V transformer circuit, is the reason for specifying the 8V (or 9V) transformer due to the 7805 regulator needing a minimum voltage of 7.5V for it to operate?
Sorry if all the questions sound dumb.
Hero999 said:Don't worry about it 1A is far more than your PIC and optocoupler emmitter will ever use, just use the 1VA or 1.5VA unit I suggested.
Nigel Goodwin said:If it's like the other transformers (and I presume it is?), then it has TWO secondary windings (this make it far more versatile), paralleling them gives you the 1A you're looking for!.
NewcastleSAR said:Hi Nigel..
I think things are staring to click together now.
Having just studied a transformer circuit on the Internet and applying the 15VAC value if I wire the two secondaries together in series, it doubles the voltage but keeps current at same level but wiring in paralled keeps voltage at same level but doubles current.
Is that correct?
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