When the capacitors of a P.S. start to fail it is very possible that we have problems in the circuits that it feeds. The reason is the ripple that appears at the exit of D.C.
This circuit is composed of three blocks but we only need the last if you want to make it.
- A P.S. (top left)
- A variable load circuit (top right)
- A ripple detector circuit (bottom right)
Don't touch the bottom left circuit'cos is to make a better visual reference.
The components are named numbering from left to right and from top to bottom, so that the potentiometer 1 corresponds to the one on the top right. This regulates the load at the exit of the P.S. and it is what you must to touch to see the effect in the output signal.
We also have a switch that allows you to completely eliminate the load on the power supply.
The detector circuit has the potentiometer 2 that allows to adjust the level of comparison between a reference signal (battery) and the maximum ripple level that we are willing to allow.
FUNCTIONING:
As the circuit starts, we will wait (~10s) for the usual ripple in a circuit with a small load to be seen on the screen. Once we see the ripple and the green line below this we can increase the load by touching the potentiometer 1. With this we will see perfectly how the ripple increases in amplitude and the level of continuous descends approaching the green reference.
If we increase the load much more we will see how the ripple signal gets to exceed the green reference limit making the red and green LED turn on alternately.
If we use a bicolor LED diode this effect would be seen as a degradation of green to red through its intermediate yellow and orange colors. Of course without flicker since the oscillation frequency is 100 Hz, if we use a non-switched power supply.
The circuit can be improved since this is quite basic.
This circuit has the function of detecting the moment in which a power source begins to have curling problems. With that we will avoid unnecessary shutdowns like those of a laptop that feeds itself from the electric network exclusively. in that moment you have to open the power supply and change the capacitors
