Diodes in parallel is not a good idea and we have discussed this in an earlier post . Due to mismatch in impedance of the diodes, it will cause one of the diode to draw more current and heat up which will even conduct more current due to their positive temperature coefficient. So that diode, due to heat conducts more and this is known as thermal runaway. And that diode fails when the current exceeds its maximum capacity.We can visualize this mismatch in impedance with the help of output voltage waveforms of the diodes. I have used 2 1N4007 diodes from the same strip. I provided 5V on the anodes of both the diodes and drawn around 100mA (not a constant load) of current across them and checked the voltage at the output of each diode. The one which has low voltage drop draws more current and will heat up when the current reaches near its capacity.Look at the voltage waveforms and the mismatch in the output which is the result of mismatch in impedance of diodes. By zooming we get this:Then, I added a small resistance across each diode to stabilize the network and took the results.The waveforms look much better but you can still observe some non linearity along spikes. So we conclude the same thing here that it is always better to use a diode of high current carrying capacity or an extra diode in the parallel network.I hope you found this useful. Thanks for reading!