I have been working on a DC dual-output power supply, and have received some great help from the forum on a couple things. I now have this idea to switch +5V into the negative output, which would allow me to convert the negative output into a fixed 5V source (when the negative output is already adjusted down to 0V). My question is, will this work with only a SPST switch?
Here is my logic as to why it will work: Once the negative output is adjusted to 0V (bottom 5K pot down to 0Ω), shorting 5V to that point will not interfere with anything because 1) the LM337 holds 1.2V across the 208Ω resistor no matter what, and 2) the 1uF capacitor to ground will stop the 5V from shorting to ground. I might be going wrong when it comes to the fact that I am connecting 5V to the output of the 337. Will current be sent to or away from the chip in a way it shouldn't be sent?
Circled in red is what I was thinking of doing. Something about it doesn't seem right but I can't quite put my finger on it. Does anyone know if this is a good/bad idea, or what techniques I can use to analyze this to find out if there is a problem?
Here is my logic as to why it will work: Once the negative output is adjusted to 0V (bottom 5K pot down to 0Ω), shorting 5V to that point will not interfere with anything because 1) the LM337 holds 1.2V across the 208Ω resistor no matter what, and 2) the 1uF capacitor to ground will stop the 5V from shorting to ground. I might be going wrong when it comes to the fact that I am connecting 5V to the output of the 337. Will current be sent to or away from the chip in a way it shouldn't be sent?
Circled in red is what I was thinking of doing. Something about it doesn't seem right but I can't quite put my finger on it. Does anyone know if this is a good/bad idea, or what techniques I can use to analyze this to find out if there is a problem?