Tagged Questions

1
vote
3answers
129 views

Charging a low-voltage high-C capacitor. Efficiently

I'm currently upgrading my wind-up torch - upon opening it, I found the manufacturers had been quite sneaky in that the circuit is EITHER windup OR battery powered - worse, the batteries are ...
5
votes
1answer
266 views

Using a Zener diode as voltage reference

I want to use a zener diode as a voltage reference to the the PIC18F2550, as the analog V+ reference. I am planning to use this zener diode, but I am not sure how to calculate its values. I am ...
5
votes
3answers
184 views

Dropping voltage for red channel on RGB LED

I'm looking at a Multicomp OSW-8349 RGB LED, which has a Vf of 3V min / 4V max for the green and blue channels, and a Vf of 1.8V min to 2.8V max for the red channel, at 350mA. I'm planning on ...
6
votes
2answers
130 views

Setting a part's VCC slightly lower than board's supply voltage

I'm interested in using the undervoltage detection feature (in addition to the primary function) of this chip. This IC draws 6 uA (microamps), and accepts any VCC between 1.6V and 5.5V. The ...
-5
votes
1answer
186 views

diode nightmares

Let me start by saying I am a complete amateur trying to stumble my way through some pretty basic PCB design, and I have run into a problem selecting diodes. The PCB I am designing will be for some ...
-1
votes
3answers
1k views

Zener Diode for Minimum Voltage Regulator

I forgot the name of it, but I remember one post where it said that you can use a zener diode as a "minimum voltage regulator". I don't think I used the right term for it, but here's what I'm doing. ...
3
votes
2answers
4k views

5V to 3V, calculate resistor value (or use diode?)

I want to connect this dv motor to the 5V output of an Arduino board. Of course I need to get the 5V down to 3V in order for the motor to function correctly. I've read that I could use a diode with ...
7
votes
2answers
971 views

zener diode voltage regulator

(Sorry, my workplace blocks access to the website for the Java based circuit simulator that everyone uses to put helpful schematics in their posts.) I'm having trouble understanding the simple ...
3
votes
2answers
3k views

Use diodes to obtain lowered DC voltage?

I am building a digital voltage gauge for my motorcycle for fun. I am buying a nice little display which has common ground, so that I can provide 5 and 12 volts from the same source. I was hoping to ...