Hello everyone,
I am making a trial 12V DC power supply with a transformer, and choke I already had and some salvaged capacitors from an old defunct project - so no investment apart from some diodes, really mostly for learning.
I have not yet got back my old 15V transformer that a friend is using so I found an old one wall wart 15v to start to understand and explore.
Well this is the current circuit I am 'comparing' simulation from measured
(for my real 12VDC I am going to build I will use the twin 0-15 transformer I have in series to give 30vAC I think to be able to get the noise down, according to simulations)
The current draw is 340mA Anyway this is the circuit and below is the measurements from an oscilloscope on DC and AC coupling.
The crazy thing is in actual measurement that last filter ADDS NOISE!! and the overall noise is way off e.. VC2 27mV predicted and 232mV measured?
Any thoughts?
VC1 17.1V DC and 5.3v p2p
VC2 13.5V DC and 232mV p2p
VC3 8.86V DC and 720mv p2p
I am making a trial 12V DC power supply with a transformer, and choke I already had and some salvaged capacitors from an old defunct project - so no investment apart from some diodes, really mostly for learning.
I have not yet got back my old 15V transformer that a friend is using so I found an old one wall wart 15v to start to understand and explore.
Well this is the current circuit I am 'comparing' simulation from measured
(for my real 12VDC I am going to build I will use the twin 0-15 transformer I have in series to give 30vAC I think to be able to get the noise down, according to simulations)
The current draw is 340mA Anyway this is the circuit and below is the measurements from an oscilloscope on DC and AC coupling.
The crazy thing is in actual measurement that last filter ADDS NOISE!! and the overall noise is way off e.. VC2 27mV predicted and 232mV measured?
Any thoughts?
VC1 17.1V DC and 5.3v p2p
VC2 13.5V DC and 232mV p2p
VC3 8.86V DC and 720mv p2p
Yeah I have been using the initial from 0 to see the speed and any ringing from the choke, and then 4S or later to see the steady state.
What sort of response time should I consider fast to get to full voltage, and slow?
Use a stepped load current to assess the power supply response to a transient load change (eg. from an amplifier type load). Your existing circuit indicates a significant damped ring at about 4Hz.
You need to be careful with probe grounding, and power supply grounding, when trying to assess secondary side ripple and noise, as indicated by rayma. Did you ground the secondary side or leave it floating. Did you use a probe with a long gnd lead and clip, and where did you connect the clip to? Is the 'noise' just low frequency (twice mains frequency) ripple, or higher frequency noise, that is giving the p-p signal voltage?
You need to be careful with probe grounding, and power supply grounding, when trying to assess secondary side ripple and noise, as indicated by rayma. Did you ground the secondary side or leave it floating. Did you use a probe with a long gnd lead and clip, and where did you connect the clip to? Is the 'noise' just low frequency (twice mains frequency) ripple, or higher frequency noise, that is giving the p-p signal voltage?