rf distance measurement

Started by chris in sci.electronics.design3 months ago

> Anyone know of any ICs designed for measureing distances with RF? I'm thinking in terms of 10 feet, 100 ft, and 500 feet with resolution to one...

> Anyone know of any ICs designed for measureing distances with RF? I'm thinking in terms of 10 feet, 100 ft, and 500 feet with resolution to one foot. The basic method of one device emitting a signal and another echoeing it back would be attractive. > Any recommendations? > > Hul Dunno about ic's, but I would look at 10 GHz gunn diode intruder alarm modules as a starting point.


Zenering a big transistor

Started by George Herold in sci.electronics.design5 years ago 57 replies

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...


speaking of substrate diodes...

Started by Anonymous in sci.electronics.design1 year ago 2 replies

leads to this one... https://www.dropbox.com/s/cgaxalnn3hhf315/RRIO_Logamp.jpg?raw=1 where we use the substrate diode of a RRIO opamp as a...

leads to this one... https://www.dropbox.com/s/cgaxalnn3hhf315/RRIO_Logamp.jpg?raw=1 where we use the substrate diode of a RRIO opamp as a logarithmic current-to-voltage converter. There are better ways to do this, but maybe none so cute. -- Father Brown's figure remained quite dark and still; but in that instant he had lost his head. His head was always most valuable whe...


fast diodes gone

Started by John Larkin in sci.electronics.design11 months ago 7 replies

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


Finding LTspice Models

Started by Ricky C in sci.electronics.design3 years ago 13 replies

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


guard ring?

Started by John Larkin in sci.electronics.design4 years ago 39 replies

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...


BJTs as ultra low leakage protection diodes

Started by Ebrahim in sci.electronics.design13 years ago 51 replies

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(


Digital transistor?

Started by Sylvia Else in sci.electronics.design8 months ago 13 replies

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...


8051F020 series, 5V tolerant input schematic?

Started by Joerg in sci.electronics.design9 years ago 89 replies

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...


How about it? Experiments of the third kind , take 999999.

Started by Jan Panteltje in sci.electronics.design11 years ago 59 replies

This is an idea for an experiment I may or may not do. The background: There have been reported seasonal variations in radioactive decay in the...

This is an idea for an experiment I may or may not do. The background: There have been reported seasonal variations in radioactive decay in the past. Now If I took a simple tritium light, and a good quality photo-diode, put both in a light proof box, and logged that with a 10 bit PIC ADC with a decent Vref for say a year to FLASH, say 1 sample / hour, run the whole thing of some battery. ...


Generating this negative pulse?

Started by Terry Pinnell in sci.electronics.design4 years ago 17 replies

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...


LDO regulators whose outputs can be ORed together

Started by Peter in sci.electronics.design1 year ago 16 replies

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


PIN diode

Started by Anonymous in sci.electronics.design1 year ago 76 replies

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...


BJT base current 1/f noise

Started by Phil Hobbs in sci.electronics.design5 years ago 87 replies

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...


Flybuck Cockroft-Walton

Started by Phil Hobbs in sci.electronics.design3 years ago 211 replies

Hi, All, This is for a flexible photoreceiver board intended for use with PIN diodes, silicon and InGaAs APDs in both linear and SPAD mode,...

Hi, All, This is for a flexible photoreceiver board intended for use with PIN diodes, silicon and InGaAs APDs in both linear and SPAD mode, and MPPCs. We've been doing a fair number of proof-of-concept systems for technology licensing, and it would be nice to have a few dozen front end boards that can be used for everything from nanowatt PIN diode detectors to an MPPC front end that wi...


Fun experiment with BF245-C

Started by Jan Panteltje in sci.electronics.design11 years ago 19 replies

Got some BF245-C N channel JFETS from ebay. Wanted a quick check to see if these were actually FETS... Multimter on diode range, plus on...

Got some BF245-C N channel JFETS from ebay. Wanted a quick check to see if these were actually FETS... Multimter on diode range, plus on drain, - on source. The way I usually test these is apply some voltage to the gate to see if they conduct / do not conduct (wet finger). But in my other hand (one hand the 2 probes on the FET) I had the plastic bag with the rest of the FETS, it detects ...


~$50 DMM

Started by George Herold in sci.electronics.design2 weeks ago 24 replies

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...


some BFP640 SiGe measurements

Started by John Larkin in sci.electronics.design7 months ago 24 replies

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?

Started by Jim Thompson in sci.electronics.design5 years ago 11 replies

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...


Spice Diode Modeling of Forward Overshoot & Reverse Recovery

Started by Jim Thompson in sci.electronics.design5 years ago 98 replies

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...