Thurlby-Thandor Right Hand Supply with new switch and other modification. The other modification involves the removal of a capacitor and the replacement of a resistor with a diode.
Plot 33: Right hand Supply, 5V, 158mA, damping off.
Plot 34: Right hand Supply, 5V, 158mA, damping on.
Plot 35: Right hand Supply, 5V, 158mA, damping on.
Plot 36: Right hand Supply, 5V, 158mA, damping on.
Plot 37: Right hand Supply, 5V, 844mA, damping on.
Plot 38: Right hand Supply, 5V, 844mA, damping on. Zoom in on output spike.
Putting capacitors on the output of the supply can remove the short spikes.
Plot 39: Right hand Supply, 15V, 166mA, damping on or off makes no difference to the performance. 22uF electrolytic across output of power supply.
Plot 40: Right hand Supply, 15V, 166mA, damping on. Same as previous but without capacitor.
Plot 41: Right hand Supply, 32V, 1000mA, damping off. With 22uF electrolytic on output of supply, scope trace looking at the load end of the harness.
Plot 42: Right hand Supply, 32V, 1000mA, damping off. With 22uF. Same as above but looking at output of supply.
Plot 43: Right hand Supply, 32V, 1000mA, damping off. As previous but without capacitor.
Plot 44: Right hand Supply, 32V, 1000mA, damping off. Turn off with no capacitor.
Plot 45: Right hand Supply, 32V, 1000mA, damping off. Turn off with 22u.
Check again at different volts that a capacitor removes the "fast" spikes.
Plot 46: Right hand Supply, 5V, 780mA, damping off. 22uF
Plot 47: Right hand Supply, 5V, 780mA, damping off. 22uF as above but switch off.
Plot 48: Right hand Supply, 5V, 650mA, damping off. Zoom in a bit, 200uS rather than 400uS. See a spike.
Plot 49: Right hand Supply, 5V, 670mA, damping off. Zoom right in. 22uF now has 100nF ceramic across it. Spikes still there, if only 10-20nS long.
Plot 50: Right hand Supply, 5V, 670mA, damping off. Another example with the same conditions.
Plot 51: Right hand Supply, 5V, 92mA, damping off. Same agian lower current.
Plot 52: Right hand Supply, 5V, 92mA, damping off. As previous but different time base.
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Writen by Jason A Tandy 5/4/01