Yep, shows a nice square wave from the cal terminal
While I wouldn;t want to challenge the 'rightness' of what you say Walter, my initial thoughts are that to provide such an artifical power source may lead to probs when the circuit has to eventually face the real world.
Isn;t it better to design so that the circuit handles the real world of power surges etc? Rather than find this out later?
David
"quietguy" wrote in message news: snipped-for-privacy@REMOVE-TO-REPLYconfidential-counselling.com...
IME, the first time you power up your circuit, the question is not usually "how well does this handle real world conditions", it's "did I wire this thing up the right way or not". If the answer is "or not," you'd rather find out when the voltage on it is about a volt, not when it's 5v and too late.
David's right that there are circuits that don't handle a gradual ramp up in power; latchup, oscillation. But personally I'd worry less about that than about zapping an untested circuit with full juice.
Current limiting is obviously a very important feature in a power supply. With good current limiting many other sins are forgiven. Sometimes I start the circuit at full voltage but with the current limiting set to zero, and then ramp in the current instead of ramping up the voltage.
OK thanks Walter. Having just got back into electronics after a 30 year break, I am not used to all the luxeries that are around today - Back in those days playing with my Exidy scorcerer and a bunch of TTL interfacing stuff it was a matter of getting right 1st time!
But times have changed, and I need to change too
Thanks for the good advice
David
Walter Harley wrote:
Yes, adjustable current limiting is an essential feature of any good power supply. Gotta watch it sometimes though, one setting might be OK for the steady state current requiremens of the circuit, but the power on current requirement is often much larger. So the current limiter will kick in for a brief period and can cause latch up problems as I mentioned. Can be really hard to track down if you don't know what's happening.
If you have a current limited supply then the general rule is as you mention - set the volts you want and ramp up the current. If you don't have a current limited supply then you would do the opposite and ramp the volts up and watch the current meter.
Dave :)
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