There used to be a bunch of low-barrier schottky diodes with Cjo < < 1 pF and equivalent series resistance < 5 ohms, SC79...

There used to be a bunch of low-barrier schottky diodes with Cjo < < 1 pF and equivalent series resistance < 5 ohms, SC79 package. BAT63 SMS1546 SMS3927 but they seem to be all gone. Strange. SMS3922 is available, with C=0.7 pF and Rs = 9 typ. Maybe I can use a small phemt as a diode. It seems as if quantity-billion ICs keep killing off fast discrete parts. -- If a man wil

I'm using a TIP31C (pnp in to-220 pac) as a temp sensor (diode connected) There's a couple of depletion fets in series as current limiters....

I'm using a TIP31C (pnp in to-220 pac) as a temp sensor (diode connected) There's a couple of depletion fets in series as current limiters. (LND150) The b-e junction starts to zener at ~30 V (only two tested so far). So I've got ~1.5 mA flowing at 30 V. Is this going to damage the junction? Will it take time? I'm going to measure forward voltage again after zenering for 15 minutes. Sho...

LTspice is a nice program... well, it's ok in many respects and great in others. But it can be a PITA to find models for. I'm looking at a...

LTspice is a nice program... well, it's ok in many respects and great in others. But it can be a PITA to find models for. I'm looking at a number of possible parts to use in a new design but many of them have no spice models. I'm not so worried about finding an accurate LED model. But I'm using a Schottky diode to prevent back feeding of power through a regulator and I need a

I'm still iterating on my high-voltage pulse generator. Rev C looks very good. I've been pushing it up voltage and frequency (like,...

I'm still iterating on my high-voltage pulse generator. Rev C looks very good. I've been pushing it up voltage and frequency (like, 1200 volts and 4 MHz) and seeing what parts fry, and working on them. I have a dpak schottky diode in a sort of snubber place. According to Spice, it shouldn't get too hot, and it's soldered to all sorts of copper pours and thermal vias and stuff. It's an S...

Hello, I want is there anyone that has used a BJT instead of ultra low leakage diode(

Hello, I want is there anyone that has used a BJT instead of ultra low leakage diode(

https://www.farnell.com/datasheets/2353855.pdf I bought a few of these. I don't know what is intended by "digital transistor" since the...

https://www.farnell.com/datasheets/2353855.pdf I bought a few of these. I don't know what is intended by "digital transistor" since the charge storage time defeats any attempt to use them at a high frequency, and there's no way to add a Schottky diode to prevent saturation, or a speed-up capacitor across the base resistor. I'm using this and the corresponding PNP type to do level shift...

Folks, Got a Silicon Labs 8051Fxxx with 5V-tolerant ports. In the abs max it says 5.8V is the limit. Well, if one uses the typical diode...

Folks, Got a Silicon Labs 8051Fxxx with 5V-tolerant ports. In the abs max it says 5.8V is the limit. Well, if one uses the typical diode against the 5V rail it could go slightly above 6V in case of a really big jolt. Since this 8051 does not have a 5V supply but just VDD (which hangs on 3.3V in this case) there can't be any parasitic substrate diodes dumping into a rail. Does anyone kno...

I have a couple of simple 555 monostables, the first to delay the triggering of the...

I have a couple of simple 555 monostables, the first to delay the triggering of the second. https://www.dropbox.com/s/6uboy3fgd0ixhxa/GenerateNegPulse-1.jpg?raw=1 But I'm struggling to extract the brief -ve pulse required for the Main mono. I thought it would prove simple. But bread-boarding various combinations of R, C, diode and NPN or PNP transistor has so far not yielded a winning comb...

Sometimes one needs to power a circuit from one source or another. Most LDOs, or indeed most normal regs, feed current back up to the source....

Sometimes one needs to power a circuit from one source or another. Most LDOs, or indeed most normal regs, feed current back up to the source. LDOs tend to use a PMOS pass transistor which has a parasitic diode. I am doing a design where I am using the Ricoh R1191 for this https://eu.mouser.com/ProductDetail/Ricoh-Electronic-Devices-Company/R1191N033B-TR-FE?qs=%2Fha2p yFaduhEV6ZG3xOqbaXpS

I want to inject a 100 ps test pulse into a 50 ohm transmission line, tee-wise, sometimes, from a 25 ohm source. So I need a series...

I want to inject a 100 ps test pulse into a 50 ohm transmission line, tee-wise, sometimes, from a 25 ohm source. So I need a series switch. I'd never paid much attention to PIN diodes... they are RF stuff. But this one is shocking: https://www.mouser.com/datasheet/2/249/MADP_008120_12790T-1921620.pdf 2 ohms on, 0.14 pF off. And that's packaged. Chip and beam-lead parts are even bette...

Is horrible. I'm just debugging a nice diode laser controller for one customer and getting ready to do another one for another (much better)...

Is horrible. I'm just debugging a nice diode laser controller for one customer and getting ready to do another one for another (much better) customer. It uses a ZXTP25020 PNP with a biggish degeneration resistor and two-pole bypassing of the base to get low noise at high frequency. Turns out the 1/f noise is atrocious. The total noise from 2 Hz on up is only a couple of PPM, but it sho...

Hi guys! Long time no smell.* I miss you guys, but I've been doing almost zero electronics. (I lurk every now and then) So my son wants a...

Hi guys! Long time no smell.* I miss you guys, but I've been doing almost zero electronics. (I lurk every now and then) So my son wants a cheapish DMM for Xmas. What brand should I look at? Extech? Searching this Klein tool one looks nice. Klein Tools MM400 Multimeter, Digital Auto Ranging, AC/DC Voltage, Current, Capacitance, Frequency, Duty-Cycle, Diode, Continuity, Temp 600V ~$50 on a...

https://www.dropbox.com/sh/tgu2ozch3rbgglk/AABI3U3_iexb69UHWoRIzm-Ma?dl=0 Interesting. The high junction drops might be the SiGe, or just...

https://www.dropbox.com/sh/tgu2ozch3rbgglk/AABI3U3_iexb69UHWoRIzm-Ma?dl=0 Interesting. The high junction drops might be the SiGe, or just the tiny junction size. It would make a decent 0.3 pF 13 volt diode. I might make an oscillator and evaluate phase noise/jitter. An x-ray would be cool. We need a high-res xray machine. -- If a man will begin with certainties, he shall e...

Anyone Have Spice model for JFET IF400? It's only used as a diode in the discrete circuit I have been asked to model behaviorally, but it's...

Anyone Have Spice model for JFET IF400? It's only used as a diode in the discrete circuit I have been asked to model behaviorally, but it's the only model I haven't been able to find :-( ...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations | et | | Ana...

Nothing like a PhD telling me something can't be done to get my solver genes working double-time... Over baby-back ribs at Firebirds this...

Nothing like a PhD telling me something can't be done to get my solver genes working double-time... Over baby-back ribs at Firebirds this afternoon I realized how to parameterize my method. But all the information I have is from "peer-reviewed" semi-BS IEEE papers. Would someone be so kind as to take data on something common like a 1N914... forward overshoot and reverse recovery at va...

I am working on a simple USB charging circuit. Normally, the 3.6V NiMH bat= tery is connected to the device via the NC contacts of a relay. ...

I am working on a simple USB charging circuit. Normally, the 3.6V NiMH bat= tery is connected to the device via the NC contacts of a relay. When conne= cted, a 5V relay switch the battery to charge via a diode. So, a fully char= ged battery is around 4.2V. As someone suggested, i will put a parallel R = & C to reduce the hold current of the relay.=20 Questions: 1. What is the minimum ...

I'm interested in how the design of consumer AM/FM radios has evolved over time, particularly since digital tuning/ PLL synthesizers came on...

I'm interested in how the design of consumer AM/FM radios has evolved over time, particularly since digital tuning/ PLL synthesizers came on the scene. Some early (1980?) PLL receiver schematics I've seen show the LC front end tank being tuned by a varactor diode. I'd imagine for several reasons one would want to eliminate the complexity of this kind of front end setup if at all pos...

This is an improved version of the one in the X-chapters. The dumb summer should be smarter to optimize s/n. If we digitize V1 and V2 and do...

This is an improved version of the one in the X-chapters. The dumb summer should be smarter to optimize s/n. If we digitize V1 and V2 and do some tweaks, that should work. BFT25 is sadly EOL. Its c-b junction is about the best diode anywhere. I'll have to find a comparable part somewhere. Version 4 SHEET 1 1192 680 WIRE -16 -304 -64 -304 WIRE 32 -304 -16 -304 WIRE 288 -304 256 -304 ...

Hi guys (and dolls), So if you read in JL's TI opamp thread, I am having noise issues in our laser diode. I turns out (I think) that the extra...

Hi guys (and dolls), So if you read in JL's TI opamp thread, I am having noise issues in our laser diode. I turns out (I think) that the extra noise is coming from my Piezo drive. The original circuit used a PA141 from Apex. (I can't find a schematic on-line, but I have a hard copy.) Several years ago this HV opamp went away and the recommended replacement from Apex was the PA314 http...

Hi all I am playing around with a solar lamp, pretty simple like this https://www.pinterest.com/pin/540150549038731182/ However I do not...

Hi all I am playing around with a solar lamp, pretty simple like this https://www.pinterest.com/pin/540150549038731182/ However I do not (yet) have D2. D1 in my case is a Schottky 1N5818, and my battery 7.2V I am surprised how much reverse current I can get through the diode. Without the solar cell, it does not turn on. There is enough current through D1 to the transistor to turn the wh...