Secrets of the Control Voltage Pin on a 555 Timer

[@georgechambers3197]

555 timer the swiss army knife of ics. thanks for the video!

[@SpectrumDIY]

💯

[@davidbee3704]

I love the way you present - you are a great teacher. Just a tip: maybe get yourself a small desktop whiteboard (say A3 paper size) and use that for your sketches. Whiteboard markers have a thicker line and are easier for your viewers to see than a ball point pen. Keep the videos coming. Love your work. 👍

[@davidbee3704]

@Bence Bujdosó Fair point. And why waste money on a whiteboard? I'm a tightarse engineer and write on the back of used envelopes that I collect. 🙄

[@davidbee3704]

@Bence Bujdosó I'll keep my hypocritical mouth shut LOL

[@mikehensley78]

Triple nickel timers. still keeping us busy after all these years. :)

[@tonyguerich9854]

Paul the Living Breathing IC Timer Cookbook...most of the ICs in there are gone but the 555 lives on.

[@ted2704]

"Because I was in the wrong hole".....been there too buddy.

[@mattmiller220]

I’ve realized that you can use pin 5 (input a voltage, like from an antenna receiver) to make an analog to digital encoder…

[@nikolatesla1077]

I built a regulated hv boost converter to drive nixie tubes with this 10 years ago .. Take a small portion of output voltage through a transistor onto pin 5 and u have regulation

[@Timsturbs]

tell about connecting R1 to a diode to 555 output instead of vcc i meant: output - diode - R1 - C1 for charging part and C1 - R2 - 7 pin for discharge

[@GORF_EMPIRE]

Excellent tutorial...though at my age duty cycle can also mean how regular one is. :D

[@markrhine5809]

Dear Sir, Very interesting video, very good, you do such a good job of explaining the videos, I enjoy your channel and will continue to watch more videos. Nice job!! Keep up the good work!!!

[@leroycasterline1122]

I've been enjoying your videos and just noticed your dolphins. Bravo Zulu from a fellow (much older) bubblehead.

[@learnelectronics]

Thank you. Boomer STS "We hide with pride"

[@leroycasterline1122]

@@learnelectronics Boomer EO. "We care enough to send the best" (picture the t-shirt with a mushroom cloud above the text, a play on the Hallmark Card ad). I was on the Edison (610). Speaking of 'hiding with pride', one time we transitioned east to west via the Panama Canal,and once we hit the Pacific on our way to Bremerton, we participated in anti-sub drills with a group of skimmers out of San Diego. We started out at ultra quiet, and by the time we were done with the exercise we were doing ahead-full to back-emergency crash backs and they still couldn't find us! Fun for us, not sure how much fun they were having...

[@sheebanh8140]

Please explain the design of circuit, that's how the values of resistances determined

[@hardbrocklife]

You better keep an eye on you health old man. I got a lot to learn from you yet ;)

[@michaelrobert4094]

Thank you, Paul, I have been wondering about pin 5 of the Triple five-timer for a while.

[@swishpan]

Nice, this is much easier than the diode stuff! Thanks for sharing

[@Big74Mike2012]

Damn man... you have GOT to get some sort of microphone shield/filter!! It's extremely hard to listen to the entire video because we get to hear every little sound your body is making! Every breath you're struggling to take, every parting of your lips as the spit snaps back onto one lip or the other, the spit accumulation at the corners of your mouth, every swallow as you try to reduce the amount of previously mentioned spit, etc., etc., etc... I couldn't get through the first 1-2 minutes!

[@m3sca1]

was about to put that pin 5 to ground with the mentioned cap according to the schematic i am following... now i think i will do this instead.

[@MechanicForGMCCars]

so question what is the 4 pin GM Ignition Module supose to by called? It uses the MC 3334 ic chip wire diagram. That thing confuses my I tryed to use 500k potenciometer on that thing suposedly to retard slightly ignition timing so my car can easely start in winter time how ever it ended up totali different insted of compresion I ended up fiering at exaust stroke and the engine was choked lot in power didnt work as planed but it did retarded the ignition timing I ques I used speaker wire and the distance from ignition module to potenciometer back to ignition coil or to ignition module cant remember reali how I hocked that thing up any way the resistance in wires caused havoc. I wasnt reali happy about it. It gets even wurse when I try to use hv ceramic capacitors on my ignition coil it messes up the Delco 12 si voltage regulator starting cutt in current . So Im realy anoyed what to do and how to replicate this circuet struggeling to finde any thing similar that is cloosed loop and more variabel .So did ever some one tryed to use remote controled variabel modulstors or some sort of remote controled relays? Im realy desperate at this point I like my car but the ignition system is shiti expeciali in winter its hard starting that car.

[@rdpoulson]

Highly excellent! Please do more teachings on the 555 timer

[@forastero233]

timer 7555 biestable como funciona profe las terminales 6 = gnd y 7 esta sin conexion, gracias

[@HappyHermitt]

I'd love to use one to build a motorcycle helmet blinker. Wireless, of course.

[@Inquire98]

'GOOD'😁 very good 👍🏿

[@mikeoliver3254]

555 are so much fun, I’ve been working on a sequencer using a 555 and a cd4017. Hopefully I’ll get it sounding good at some point. Great video my friend, you rock Paul.

[@rodriguezfranco3839]

could you feed an audio signal to pin 5 , I want to use it to play music with my tesla coil feeding the pin 5 on the interrupter 555 timer , but I am not sure how to do it plus I do not want to burn my cellphone or whatever I use to feed the audio signal , could you make a video about it ?

[@bertspeggly4428]

How would you change the duty cycle and frequency individually?

[@Chucklesrailarchive]

Great program but I’m lost when the maths comes in.

[@sayantanmaiti2513]

Basically you can make a mini FM generator using this control voltage pin. With natural frequency of oscillation as the carrier frequency. The audio signal at control voltage pin

[@stevetobias4890]

Can also change one of the 10k resistors to a pot you will be able to bypass the manufacturer tolerances.

[@KrumpusPlunk]

replacing one of r1 or r2 with a potentiometer wound be another way to control the frequency, right? and if you chose r1 comparatively small and replaced r2 with a potentiometer you'd have a 50/50 square wave with controllable frequency?

[@Sandeepan]

"Nothing happened", I se what you did there

[@mikebond6328]

Pin 5 should be called the offset pin.

[@petersnyder1642]

Hey Paul. I’m looking to purchase a good scope for my bench. What do you recommend ? I see you have 2 listed in your equipment list. Nay advice is appreciated. Thanks for the control pin vid.

[@learnelectronics]

The Rigol 1054Z is probably the best value of features vs price at $359. You can't go wrong with it. But if you want something more affordable, the Hantek DSO5072P is about $100 cheaper. 2 channel only and no protocol decoding. But only you know what features you need.

[@mikeydoritos]

This would basically be a PWM knob for the Atari Punk Console, right? Should sound cool.

[@KrumpusPlunk]

but it looks like it's affecting frequency and pw at the same time? it looks like it just changes the high-time (or low time?)

[@larryb.lindsay2366]

Nice one. I learned another nice tip. Thanks

[@lenslens7379]

We can use pin5 to make a VCO

[@dalenassar9152]

THANKS FOR THIS VIDEO...I JUST LOVE "PIN-5 APPS"!! One thing I made was an infrared LED modulator. I used the same type of scheme used in the TV remotes. They usually run at about 38kHz. However, about in the 90's, Vishay came out with with a Three-pin IR receiver (TSOP7000) that operated at an amazing 455Khz! I was able to use this as a carrier frequency for the full audio range of frequencies! With a 555 driving a powerful IR LED tuned at a center freq of 455kHz, THROUGH PIN 5, I could modulate audio over a long range...I actually got about two miles range with a single pulse modulated LED, and Fresnel lenses at each end. The alignment was an absolute nightmare!...we used rifle sights and a pair of VERY heavy tripods. ...I'll cut here. BTW: I think you would have better luck with a lower resistance pot [50K (actually ~25k) out vs three 5K in series: (~3.3k ohm input).] It is VERY interesting to use use the 555 with a +/-5V dual supply and modulating pin 5 with the output wave-forms of the MAX038 function generator

[@phrankus2009]

Short and to the point .. In .. Out .. Done! THANKS. SAVED TO: DC ELECTRONICS THEORY SAVED TO DC ELECTRONICS SOURCING SAVED TO CONTROL & DISPLAY

[@mscavsfan]

great vid !!! Thanks ..... Can you do a video on how to convert the square wave into a sine wave ? Is that easy to do ?

[@nikolatesla1077]

Yes series resistor and a cap to ground . Google low pass filter ...

[@JurekPrzezdziecki]

The datasheet says - precision 555 timer. Your waveform it's not precise at all. It's not so simple. First of all the waveform looks distorted. Just look at the rising edge at 500 us. You need a pull-up resistor at the output or pull-down OR BOTH as well. You need to bypass with capacitors etc... All I want to say is that: a precise 555 circuit needs a more precise explanation. Anyway, I like your channel. Good luck.

[@CuSiSound]

Thanks for the technical explanation. I used this control voltage method in both my little boxes punk console and my original Project Nine diy modular analogue synthesizer. Check out my channel to see what I did.

[@electronic7979]

👍

[@AngelloPareja]

Gracias, crack.

[@solomonferriz]

excellente.... greating from Machupicchu Perú.

[@learnelectronics]

Greetings to you as well

[@pulesjet]

BIGGER, I'M BLIND.

[@arthurfricchione8119]

excellant video very helpful. thanks for sharing your knowledge Artie😀

[@williamgomez6226]

Majestic video

[@nonsuch]

So... since the data sheets don't specify, I've always assumed PIN 5 (CV) to be an INPUT. However, when I measure it with a VOM (V Red to PIN 5 and COM Black to Ground) it's always OUTPUTTING 1/2 of VCC with nothing connected to PIN 5. So if VCC is 12V, PIN 5 will be 6V etc. This is something I never quite understood. Can you or anybody else comment on this? Thanks!!!

[@PracticalCat]

The reason why you have roughly half the voltage of vcc on pin 5 is because pin 5 is connected at a node in the center of a voltage divider. From vcc to Gnd their are two resistors in series (this is the voltage divider ) Pin 5 is connected to the middle of the two resistors. Anyone can feel free to chime in if I am wrong.

[@chrisbrett1857]

@@PracticalCat Sorry, but your explanation doesn't quite make sense to me. Looking at the internal schematic for the 555, the internal voltage divider has THREE equal resistors in series (say Ra, Rb, Rc, with Ra being connected to Vcc & Rc to Ground) . Pin 5 (Control) is connected to the node between Ra & Rb, which should therefore be at 2/3 of the supply voltage i.e. at 8V if Vcc is 12V. I assume that's why Rob Consentino is puzzled by seing 6V. I'm puzzled too, and for the same reason - I'm going to try it out for myself when I have a moment, to see if I can get the same effect.

[@PracticalCat]

@@chrisbrett1857 I see what your saying. It should be 2/3 of the supply. My bad. Weird I want to breadboard a 555 timer now and have a measure :)

[@sohelrana8376]

any one explain that briefly ........anyone share with me in details of this operation kindly.

[@michaelpadovani9566]

Unraveled a mystery in my mind, glad you mentioned application toward the end bc i couldn't think of anything offhand...you may be onto something with the synth!

[@vishalr4551]

100th comment

[@davidbee3704]

Love your videos!

[@RicardoPenders]

It's nice to see that you can change the duty cycle and frequency this easy with a 555 chip but I want to have the frequency fixed and much higher, above the frequency that we can hear.

[@DIYwithBatteries]

I never thought about pin 5. Thanks for sharing Sir. 👍

[@غريبالدار-ذ7ب]

Can you make a transmitter and receiver circuit at a frequency of 37 Hz?

[@DavidALovingMPF102]

I have been using the 555 for decades, love it, but what does the alligator do?

[@jacksonsee2746]

Thank your Sir for your demonstrating . 😀

[@agthegod9148]

Nice

[@contemporiser]

what if you feed in the output signal to a transistor switching some resistance to the pin 5?

[@minhtran7096]

Is there a way to control only the duty cycle and leave the frequency the same?

[@pleasecho2]

Doesnt changing the values of R1 and R2 do the same thing?

[@Enigma758]

I like it!

[@Dinkum_Aussie]

Loved this! Very cool thank you! 😎👍

[@andreamodiano]

Thank you, excellent point and presentation.

[@dirindirin3983]

👍

[@buitenb]

Thanks for the video , nice to see some 555 circuits !

[@miker302]

And there was I wondering how you could get a 50% duty cycle with a 555. Obvious answer here!

[@KrumpusPlunk]

another way is using a diode to bypass r2. or, if you simply chose r2 substantially higher than r1 you'd also get a roughly 50% duty cycle, right?

[@fourfourfoureightyfour23]

thank you ! you're such a good teacher !

[@mammadolimlechan]

♥️♥️♥️

[@davidrathbone6978]

buy a better mike!

[@barnabywilde374]

have Mike buy a better mic

[@markgreco1962]

First

[@LEO-xo9cz]

56th!

[@Julian_Bester]

So great thank you!

[@flemmingchristiansen2462]

Nice. What if you put an oscillator on pin 5?

[@learnelectronics]

I did that in the Atari Punk Console video.

[@bblod4896]

Cool. Peace Paul.

[@mandalouella]

Can you get capacitors where you can adjust the value of the capacitance

[@learnelectronics]

yes, variable capacitors

[@KrumpusPlunk]

@@learnelectronics cool, so that would be an ideal way to change frequency without affecting the pulse width, right?

[@microhobbyist]

Still new to the 555, but if I wanted a fixed and stable 50% duty cycle, do I need to have half of VCC on pin 5? Or is that why the suggested 0.1µF capacitor is used for?

[@blic-sx9ix]

If you just put a jumper (0 ohm) in place of R1 you will get a 50% duty cycle in a standard astable 555 circuit. No need to change pin 5. Do a search for "555 astable online calculator". Plugging in 0 for the R1 value will confirm this. Then just put the C and R2 values you need to set your frequency. Changing the pin 5 voltage seems to let you get the duty cycle below 50% which you can not do with the basic astable circuit.

[@antoineguilmain2754]

@@blic-sx9ix You can't do that. By shorting R1 you short the power supply every time the discharge transistor is on inside the IC. There is a minimum value for R1 which is around 1k depending on the power supply voltage. You can achieve a duty cycle of roughly 50% (slightly above) by making R2 have a much bigger value than R1, and because putting a large resistor value will lower the frequency, you can mitigate that by lowering the value of C1 as well. You can also try a classic astable multivibrator circuit with two transistors and two identical capacitiors and resistors instead of a 555 IC if a 50% duty cycle is critical. I hope that helps.

[@blic-sx9ix]

@@antoineguilmain2754 Thanks for setting me straight! I always use 2 resistors in my circuits but noticed that a 0 for R1 in the calculators gave 50%.

[@antoineguilmain2754]

@@blic-sx9ix No problem, I always enjoy helping others when I can. As for the calculators, i'm not surprised. They just plug the values you give them into formulas without giving a second thought about it!

[@KrumpusPlunk]

@@antoineguilmain2754 could you put a diode parallel to r2? then charging of the capacitor will only flow through one resistor and discharging through the other resistor. then if you made both R the same value, you'd have a 50% cycle

[@Naked4FunTV]

u are the boss, I wish I had better time to help out with some donation

[@KissAnalog]

Thanks Paul.