Re: Schematic question for LM138 voltage Regulator
It will somewhat improve the ability of the voltage regulator to reduce any voltage fluctuations/ripple on the input voltage source making it through to the output. You could probably do without it, but it would not hurt to include it.
Out of curiosity, what is the main power source that feeds the regulators and how much current do the motors require? Linear regulators create a voltage drop between input and output by essentially being a well controlled vyou will almost definitely need some sort of heatsinking to keep the LM138 from failing.ariable power resistor (best description I can give without going into the actual transistor circuitry design) and get rid of the excess voltage as heat (P = I*V). The more current you need and the larger the voltage drop, the more heat you have to dissipate from the device (usually assisted with a heatsink and possibly forced air cooling or even water cooling in really high power situations). The more the device heats up, the less current it can provide to the output. So the better the heat transfer out of the device, the longer the life of the device and the more power it can dissipate without damage (thus more current at regulated voltage to the load).
The TO-220 package LM317 that I wired up for providing +9V to the wireless router on darsha is powered by either a 11.1V LiPo or a 12V SMPS and is usually loaded to less than 0.5A. The power required to be dissipated from the regulator is ~1.5W depending on conditions and gets pretty warm even with a large-ish heatsink.
Please pardon the pedantry... and the profanity... and the convoluted speech pattern...
"You have failed me, Brain!"