I came across the circuit below in "Practical Electronics for Inventors" and am having a hard time understanding how placing the zener diodes between ground and the ground pin of the regulator boosts the voltage from 5V to 14V.
I understand that the breakdown voltages of Z1 and Z2 are 3V and 6V, and that they add with 5V to get a total of 14V, but I just can't see how this alters the flow of current to increase the voltage between ground and Vout.
EDIT: thank you, all! I understand this circuit now :)
https://preview.redd.it/f7v79fw62of71.jpg?width=3024&format=pjpg&auto=webp&s=84eb0a02cd1fd19119e0157557bcbea7d7c40cb5
A bit confused how to ensure lowest current loss in diode when setting up a certain voltage threshold for EXT_BOOST pin in Boost converter.
https://preview.redd.it/kdma9utps8i71.jpg?width=290&format=pjpg&auto=webp&s=0b621dcf3b3725f3688e0d15a7a6f657595c9346
I'm trying to use ISL85403 DC-DC buck-boost converter, however, I can't just use their example because I have different Vout.
My case:
Vin: 3VDC to 16VDC
Vout = 5VDC @ 2.5A
So EXT_BOOST pin must be 800mV when VBAT pin is 6.3V. You can read about it in this (p.6) manufacturer's note.
Preferably, EXT_BOOST pin shouldn't be below 200mV when Vbat is 3V.
Anyway, a bit unknown how the biasing of diode works here... Like, it's a PN junction, and a voltage threshold between anode and cathode for 4148 is ... 0.7V? per "Fig. 1 Typical Forward Characteristics", so when anode is higher than cathode the diode D1 will start conducting 10mA straight to ground. And 0.7V is about the drop across diode.
How does using diode help with setting both upper and lower threshold? Using only two resistors, as in resistor divider, sets only upper threshold when Vbat = 6.3V, EXT_BOOST = 800mV. Vbat = 3V, EXT_BOOST = 380mV (should be 200mV or lower).
How does diode change anything, the only thing I noticed by making a simulation in LtSpice is that the node EXT_BOOST can be at higher potential than the anode of D1.
I'm guessing because of R4. Btw, when doing circuit analysis, can I simplify the circuit by combining R1+R2 in series then do the parallel formula with R4? Or I can't ignore R3, diode?
So (R1+R2) | R4 = R_124
* not on a bus, but on an A register, sorry.
Hi, the community!
I've bought the kits for the 8-bit computer, and I got stuck on the second one, registers.
I have a register A (red diodes), data bus (yellow diodes), and clock. I set the A register's pins to 1, and the red diods light as expected. But when I switch the enable pin from high to low (to transfer voltage to the data bus), instead of both yellow and red diodes do light, the only yellow do (check on the video). In Ben's video, both do light. I've measured voltage on the red diodes when the enable pin is low, it's ~1.5 what is not enough for them to light. If it is a problem, why does it happen, and how to solve it?
Hi, I'm using an NPN NO inductive probe in my 3d printer which says to be rated for 4-30V currently connected to gnd, 5v and its output to a signal pin on my skr 1.4 (currently using the 3 pins on the servo connector), seeing that it's the only one with a 4v rating while most others are 6-30/6-36/10-30 I'd like to test it with 24v to see whether the accuracy is any better, for what I can see online it seems like a Zener diode rated at 5.1V on the signal to protect the board from (with the "line" of the diode towards the probe), is this a correct and safe way of doing so? I've never used a diode in a DIY project other than LEDs and don't know much about them. I ask here and not in 3dptinting because it seems strictly about electronics, I hope it's fine by the rules.
Figured I'd shoot this out here, maybe someone will more clue than I do. I'm designing a PIN diode transmit/receive switch to handle 700W pulses at about 2% duty cycle, 128us max pulse lengths. The design will be a series TX, RX dual shunt with quarter wave lengths so the PINs are on during pulses, off otherwise. Now here's my question: I threw in MACOM MA4P506-1072T PINs because they are rated 500V, 15W, but they are pricey and I think overkill. Since there will be maybe a Volt drop I estimate about 4W during pulse but since they are only on 128us could I get away with a 750mW rated PIN to save some size and money?
Any way to model the junction temp during pulses?
I'd love to learn as much as I can. I like the idea of building my own dosimeter. It's difficult to find resources for how to do that. There are some schematics but I don't fully understand how they work and how I can actually interface with a microcontroller to properly measure particle energies.
A neighbor of mine had his pc die earlier, and while getting ready to hook up my DSO) I noticed an empoty part of the board for a 3 pin diode, upoon a closer look, I noticed a 3-pin diode was missing and had definitely been there before.\
The issue is I have no idea of what kind of diode it should bhe and I can't find crap. AcePc has no documentsation, and is just a budget $80 mini-pc, that I think is an exact clone with same motherboard as the Wintel W8 and Winbound W8, since the board modekl is W89 Z8350 or whatever atom version it is.
SO, if anyone has one of these systems, I would appreciate it if you could find the type of diode inside, or just take a picture of the diode. I would also like alternative options in casde no one with a system is found quixkly. I am not familiar with diodes beyond reverse polarity prevention, current/voltage limiting, or boosting and etc. So, can anyone familiar with diodes take a educated guess as to the type of diode on the boiard. Also, what type of Didoe is a safe alternative to use? I tested the 2 positive pins of the diode pinout, and one gave me 5v and the other was 3.3v with the 3rd being ground obviously. So that was the voltages flowing intpo the diode from the pc.
