Richard, For up to 1 A there are lots of Schottky diodes in SOD-123 package, and they are not expensive. The PMEG2010ER,115 has an If of 1 A and 20 V of Vrrm with a maximum Vf of 310 mV at 1 A. Costs US$0.44 @ 1 and US$0.123 @ 1000. The STPS140Z has an If of 1 A and Vrrm of 40 V with Vf 550 mV @ 1 A. Costs US$0.26 @ 1 and US$0.089 @ 1000. In SOD-123 you will find diodes with If up to 3 A. There are lots of other packages, but I like the SOD-123 because it is small and good to assemble. Cheers, Isaac Em 17/09/2015 09:32, Richard R. Pope escreveu: > Issac, > I haven't checked it but I would say that this board probably only=20 > draws a half an amp. That is a guesstimate so don't quote me on it. I=20 > might measure it when I go back out If all of the LEDs are on that would= =20 > be another 150mAs. > Thanks, > rich! > > On 9/17/2015 7:26 AM, Isaac Marino Bavaresco wrote: >> Richard, >> >> >> You could use a Schottky diode. They usually have much lower Vf. >> >> I like the CDBA320 to CDBA380 series, up to 3 A of If and from 20V to 80 >> V Vrrm, with a Vf of approx. 0.25 V. They are not very cheap though. >> The SD2114S040S8R0 supports currents up to 8 A and has a Vf of approx. >> 0.125V for small currents, a tough guy. >> >> But there are many other Schottky diodes, with various If, Vf and Vrrm >> ranges. Some of them are very affordable. >> >> >> By the way, my friends call me Isaac. >> >> >> Cheers, >> >> Isaac >> >> >> >> >> >> Em 17/09/2015 08:57, Richard R. Pope escreveu: >>> Marino, >>> These are some really good points. I didn't put in a diode becaus= e >>> of the forward voltage drop. I'm using a 5 volt regulated supply and 4.= 5 >>> volts would be right at the limit of what a 628A will tolerate. I'm >>> going to put these suggestions away for another day. I appreciate this. >>> Thanks, >>> rich! >>> >>> On 9/17/2015 6:34 AM, Isaac Marino Bavaresco wrote: >>>> Richard, >>>> >>>> >>>> It is a good idea to always provide some sort of reversal polarity >>>> protection to circuits. It is very common for equipment to be connecte= d >>>> with the wrong polarity or a wrong power adapter. >>>> >>>> There are several approaches, suitable for various circuit requirement= s. >>>> >>>> 1) Just use a diode in series with the power input. Suitable when your >>>> circuit consumes a moderate current and you have a voltage regulator i= n >>>> the input or can tolerate a small voltage drop. >>>> >>>> 2) Use a fuse in series with the power input and a powerful diode >>>> connected cathode after the fuse and anode to ground. Your diode must = be >>>> strong enough to ensure the fuse will blow before the diode is damaged= .. >>>> The advantage is that you don't have the Vf loss from the diode when t= he >>>> circuit is operating. >>>> >>>> 3) Use a power P-Channel MOSFET with its Drain pin connected to the >>>> power supply, Gate to ground and Source as output to the circuit. This >>>> circuit can be used for voltages up to approx. 20V, which usually is t= he >>>> Gate-Source breakdown voltage. With the addition of a Zener diode and = a >>>> resistor this limit can be raised. >>>> This circuit can be used for really high currents with very little >>>> energy loss. If you add another MOSFET in series in the opposite >>>> direction plus a TL431, another smaller MOSFET and some resistors, you >>>> have overvoltage protection also. >>>> >>>> 4) Use a relay with its coil with a diode in series connected to the >>>> power input. Use the normally-open contact to power your circuit. This >>>> method can be used for any current and voltage ranges and the only los= s >>>> is the relay's coil current. >>>> >>>> Cheers, >>>> >>>> Isaac >>>> >>>> >>>> Em 17/09/2015 03:43, Richard R. Pope escreveu: >>>>> Bob and et al, >>>>> Well I just make a goof! I was very fortunate. I hooked the po= wer >>>>> to my control board up the wrong way. The PICs are tough little >>>>> monsters. Even though the power was hooked up the wrong way for almos= t >>>>> twenty minutes all of the PICs are fine. It looks like all that I >>>>> damaged were the tantalum capacitors. Wow! Good news. I'll be more >>>>> careful from now on. I appreciate all of the help that everyone has >>>>> given me. >>>>> Thanks, >>>>> >> --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .