Gilbert cell question

Started by Anonymous in sci.electronics.design3 years ago 11 replies

Apparently, when used in the continuous mode, (as opposed to the switched mode) the local oscillator input to a needs to be distorted with a...

Apparently, when used in the continuous mode, (as opposed to the switched mode) the local oscillator input to a needs to be distorted with a diode circuit. What is exactly this diode circuit -- a single diode or something more complex. Thanks in advance.


74HC74 oscillator simulation

Started by bitrex in sci.electronics.design2 years ago 36 replies

IRL I don't think there's anything this configuration of the 'HC74 could do but oscillate; with an RC network from not-Q to not-CLR and D, CLK,...

IRL I don't think there's anything this configuration of the 'HC74 could do but oscillate; with an RC network from not-Q to not-CLR and D, CLK, and not-PRE grounded. But with these models from the Yahoo LTSpice users group the LTSPice time domain looks like it manages to find some other metastable state and sits there spinning its wheels. Can anyone suggest some ICs that could bust i...


Webcam synchronization

Started by Eduardo in sci.electronics.design8 years ago 19 replies

Hi, is it possible to synchronize capture from two webcams by removing the crys= tal oscillator from one of them and using the clock from the...

Hi, is it possible to synchronize capture from two webcams by removing the crys= tal oscillator from one of them and using the clock from the other as a mas= ter clock for the two cameras? The goal is to build a stereo camera system = and compute stereo maps from disparity images. If it's not possible, is th= ere any other inexpensive solution for this problem? I currently have two L= ogite...


ring oscillator

Started by John Larkin in sci.electronics.design5 years ago 36 replies

I've never really understood ring oscillators, and I still don't. Startup is interesting. After the power supply comes up, the stages are...

I've never really understood ring oscillators, and I still don't. Startup is interesting. After the power supply comes up, the stages are identical, fully symmetric, and all the nodes hang at +2 volts. It meditates on that for about 70 ns, and then everything scatters and it soon settles down to a nice 26 MHz oscillation. The oscillation period is 5 times the sum of a stage Tpd_rise +...


Which oscillator?

Started by Anonymous in sci.electronics.design7 years ago 31 replies

Hi folks. I'm looking to choose a couple of oscillators for 3rd world construction/use, and I'm very rusty on the properties of the numerous...

Hi folks. I'm looking to choose a couple of oscillators for 3rd world construction/use, and I'm very rusty on the properties of the numerous options. What's essential: - reasonably frequency stable with quite widely varying psu voltage, eg 5-9v - discrete parts only, ICs can't be counted on to be available - common parts only, no tapped inductors etc - the minimum of parts is a major choice fa...


Learning about oscillators in LTSpice

Started by Clifford Heath in sci.electronics.design7 years ago 68 replies

I'm just getting started with LTSpice, and played yesterday with some Colpitts oscillators to my satisfaction. Today I tried a Hartley, and I...

I'm just getting started with LTSpice, and played yesterday with some Colpitts oscillators to my satisfaction. Today I tried a Hartley, and I can't understand some of the behaviour I'm seeing. In the attached circuit, I've added an emitter resister in an attempt to reduce the high collector current. Merely increasing the base resistor didn't help until the oscillator stopped entirely. Act...


NTC caps

Started by John Larkin in sci.electronics.design5 years ago 7 replies

Good guys: http://www.capaxtechnologies.com/products.htm They have NTCs in stock, or will make what you need. They made me some special...

Good guys: http://www.capaxtechnologies.com/products.htm They have NTCs in stock, or will make what you need. They made me some special 3.3pF N4700s, and we just got some N750s from stock. We have been having problems with one oscillator. Turns out that someone else shipped us a reel of NPOs when we ordered N750s. -- John Larkin Highland Technology, Inc picosecond...


2.4Ghz Oscillator

Started by Cursitor Doom in sci.electronics.design3 years ago 33 replies

Gentlemen, Has anyone got any ideas for a simple, low-power (milliWatt level) VCO for the WIFI band? Something with a minimal range of just a...

Gentlemen, Has anyone got any ideas for a simple, low-power (milliWatt level) VCO for the WIFI band? Something with a minimal range of just a few feet? I just want to ensure my phone can't access my home network WIFI unless I expressly allow it. TIA. -- This message may be freely reproduced without limit or charge only via the Usenet protocol. Reproduction in whole or part thr...


200MHz VFO

Started by George Herold in sci.electronics.design8 years ago 29 replies

Hi guys, The 200 MHz. frequency synthesizer thread got me thinking. I could use a 200MHz VFO (say 150 to 250 MHz or something like that) I...

Hi guys, The 200 MHz. frequency synthesizer thread got me thinking. I could use a 200MHz VFO (say 150 to 250 MHz or something like that) I don't need much stability, a part per thousand for a several minutes would be enough. So what's the simplest way to get there? An LC oscillator (I've got some nice tunable few pF caps) There's also a VCO from Maxim. (max2607) that looks easy. http://...


Semi manufacturer takeover - do parts change?

Started by Kluge in sci.electronics.design6 years ago 14 replies

A product has been using the HEF4060B for the last two or three decades without issue. But the last batch have issues with the oscillator...

A product has been using the HEF4060B for the last two or three decades without issue. But the last batch have issues with the oscillator starting reliably at the correct frequency (32767Hz xtal) The part originally used was manufactured by Philips. Then Philips became NXP around 2006. I'm not sure if it was taken over, renamed or whatever...... Parts branded NXP have been used i...


Help Please -- very strange oscillator problem

Started by Anonymous in sci.electronics.design4 years ago 34 replies

Could some electronics guru please help ? I have two identical(same resistor, capacitor values) implementations of an astable multivibrator. I...

Could some electronics guru please help ? I have two identical(same resistor, capacitor values) implementations of an astable multivibrator. I am using the 2N3055 and each transistor drives a coil each of a bifilar coil, whose common terminal is connected to a 12 Volt 2A(max) DC power supply. The coils is air core. The problem is that one implementation works as designed, the other does ...


PIC oscillator Q

Started by Robert Baer in sci.electronics.design6 years ago 16 replies

It seems that an un-programmed PIC will not oscillate; the OSC pins are at ground in the "raw" state, and 10Megs between them obviously will...

It seems that an un-programmed PIC will not oscillate; the OSC pins are at ground in the "raw" state, and 10Megs between them obviously will not get them to logic (linear) level. So, ASS-u-ME that the PIC is minimally programmed for an external 20Mhz crystal and one would like it to oscillate at that frequency and not higher, what changes would be needed, based on my old Semi-univ...


On-board Oscillator with CMOS 4046

Started by Miguel Cardoso in sci.electronics.design8 years ago 8 replies

Hello, I need help to determine the value of VR2 and C12 (pin 6 and 7). For my project I need a base frequency of 400 rpm and a running speed of...

Hello, I need help to determine the value of VR2 and C12 (pin 6 and 7). For my project I need a base frequency of 400 rpm and a running speed of 4000 rpm. I also determine a R26 (pin 11) at 10k for a 100k VR1. With these values, what is the value for C12? Thank you, Miguel


Anyone have an MC34063 SPICE model lying around?

Started by Tim Wescott in sci.electronics.design10 years ago 4 replies

Title says it all. LTSpice preferred. While we're on the subject -- does anyone know what the error amplifier gain is in the MC34063, and...

Title says it all. LTSpice preferred. While we're on the subject -- does anyone know what the error amplifier gain is in the MC34063, and what ranges one can expect in real life? The data sheets all call it a "comparator", but reading between the lines it's a gain stage followed by a comparator to the oscillator (which is what it has to be, to work correctly). -- My liberal frien...


Low Current LED

Started by Anonymous in sci.electronics.design7 years ago 11 replies

I have an application where I need an LED to light on about 1.1 mA.=20 It doesn't hav to be real bright, just indicate thaat a battery is good....

I have an application where I need an LED to light on about 1.1 mA.=20 It doesn't hav to be real bright, just indicate thaat a battery is good. Du= e to my wish to make it power switch free, the design is constrained. I am = sure I could probably come up with more current, but at the cost of complex= ity as well as power drain.=20 It is a pretty simple device, just an oscillator to put a ...


Orthogonality

Started by Tim Williams in sci.electronics.design7 years ago 17 replies

Is there such a thing as a circuit (or more generally, system of differential equations) where the output frequency is always orthogonal...

Is there such a thing as a circuit (or more generally, system of differential equations) where the output frequency is always orthogonal (anharmonic) to the input? Example response would be, you have an arbitrary input frequency, and you want to pick an output frequency that *doesn't* line up with the input. If you use a fixed oscillator, it'll work for some inputs, but there will be ...


DIY CRO Protection HV Probe

Started by Anonymous in sci.electronics.design8 years ago 4 replies

I have been experimenting with HV circuits that generate up to 10KVAC within the audio range. The usual oscillator and step-up...

I have been experimenting with HV circuits that generate up to 10KVAC within the audio range. The usual oscillator and step-up transformer configurations. I would like to check the output waveforms on my digital CRO but don't have a suitable HV probe, and would prefer not to spend $100+ for this one time use. Is there some arrangment of passive components I can wire between the CRO an...


PV MOSFET driver reliability

Started by Piotr Wyderski in sci.electronics.design7 years ago 42 replies

How reliable such devices are in real life? The most extreme, yet typical use case: a constantly opened N MOSFET (i.e. it should be closed only...

How reliable such devices are in real life? The most extreme, yet typical use case: a constantly opened N MOSFET (i.e. it should be closed only during exceptional scenarios), which implies constantly energized LED inside the coupler. For many^2 years. Is it an obvious no-go? One alternative is a transformer-coupled full wave rectifier driven by an oscillator I already have. Seems to be bul...


SPICE gets it wrong

Started by Tim Williams in sci.electronics.design5 years ago 74 replies

Speaking of SPICE, here's a nice little circuit: https://www.seventransistorlabs.com/Images/BakerDarlington.png I discovered the oscillator on...

Speaking of SPICE, here's a nice little circuit: https://www.seventransistorlabs.com/Images/BakerDarlington.png I discovered the oscillator on the left, when attempting to build a Darlington transistor pair with a Baker clamp. (In practice, R10 comes from a logic voltage input, and R2 is a load, often inductive. R14 is optional, but exacerbates the oscillation, making it reproducible.)...


Using earth (ground) as 0V return wire

Started by Anonymous in sci.electronics.design6 years ago 19 replies

I have a Remote Control unit I made years ago for toggling various lights, hi-fi, TV, etc. I have a few spare buttons so I'm using one as a 'Shed...

I have a Remote Control unit I made years ago for toggling various lights, hi-fi, TV, etc. I have a few spare buttons so I'm using one as a 'Shed Signal' so that SWMBO can summon me indoors occasionally. The simple oscillator circuit, feeding a miniature speaker, has its own DC power supply in the shed (workshop) and its 0V line is earthed. So is the 0V line of the RC unit in the lo