https://community.element14.com/technologies/555-timers/The 555 timer is a fundamental integrated circuit used in a variety of timer, delay, pulse generation, and oscillator applications. Learn how 555 Timers Work with our 555 Timer ebooks and 555 Timer Project Videos.en-USTelligent Community 12https://community.element14.com/technologies/555-timers/f/forum/55669/how-to-use-555-to-start-some-circut-in-delay/227690Wed, 02 Apr 2025 15:26:00 GMT93d5dcb4-84c2-446f-b2cb-99731719e767:e0307812-32e6-40ea-ab67-b6e11fe6471ajc2048The datasheet for the TI NE555 gives this for a sequential timing circuit. Have a look at the datasheet for the output waveforms and more details. www.ti.com/.../NE555 They've used a cap and resistor as a differentiator between the stages. If you've got an oscilloscope, it would be worth slapping it together on a breadboard and looking at the waveforms. If not you could try a simulator. One question you might ask yourself is, how is it safe to use the differentiator like that, given that it will produce a positive spike on the other edge (that would take the TRIG input above the supply)?https://community.element14.com/technologies/555-timers/f/forum/55669/how-to-use-555-to-start-some-circut-in-delay/227687Wed, 02 Apr 2025 14:24:00 GMT93d5dcb4-84c2-446f-b2cb-99731719e767:38526434-0ef5-4e17-a67d-372ea3d7a00fdougwYou can use a dual 555, which would be a 556. The first monostable triggers the second monostable to start after a delay.https://community.element14.com/technologies/555-timers/f/forum/55669/how-to-use-555-to-start-some-circut-in-delay/227679Wed, 02 Apr 2025 10:01:00 GMT93d5dcb4-84c2-446f-b2cb-99731719e767:57bb1298-e7d1-49d7-916c-b0f75b562d0cJWxit depends on the exact use case - would it be an one-time delay after power-on? or a delay after button press? what would be an default state of output (for example: default low, goes high after defined time from button press and stays high forever/for defined time/until some other action)? There are many such circuits when searching for "555 delay timer" on the Internet with different schematics for different use cases...https://community.element14.com/technologies/555-timers/f/forum/55669/how-to-use-555-to-start-some-circut-in-delayWed, 02 Apr 2025 07:34:00 GMT93d5dcb4-84c2-446f-b2cb-99731719e767:5456d827-bb63-4d0c-9c13-7a8c6ea8463fJakubPrazmowskiOk. I got monostable mode. I am pressing my little button and timer starts rolling. I getting HIGH on output 3 and it last some time. I wonder why how to connect it with some other circut to start rolling just after state from pin 3 will go back to LOW? I am new in electronic so any help is very welcome. Thank you very much for help. Jakubhttps://community.element14.com/technologies/555-timers/f/forum/55119/analysis-of-a-555-circuit-design-will-it-work-maybe-there-is-a-better-way/224217Sun, 22 Sep 2024 12:10:00 GMT93d5dcb4-84c2-446f-b2cb-99731719e767:bc0b3fce-cebd-4670-9a01-089a61f99a20beacon_dave[quote userid="37381" url="~/technologies/555-timers/f/forum/55119/analysis-of-a-555-circuit-design-will-it-work-maybe-there-is-a-better-way"]I'm not sure of the design. It looks like nothing I have found.[/quote] Looks like it has been taken from the left half of this bipolar LED driver circuit: https://web.archive.org/web/20140910104816/http://home.cogeco.ca/~rpaisley4/LM555.html#15https://community.element14.com/technologies/555-timers/f/forum/55119/analysis-of-a-555-circuit-design-will-it-work-maybe-there-is-a-better-way/224215Sun, 22 Sep 2024 06:41:00 GMT93d5dcb4-84c2-446f-b2cb-99731719e767:e5009d0a-3d8b-407b-8fc8-3858f1541243aswinvenuPin 5 is the Control Voltage (CV). Internally this voltage is generated using a voltage divider. Adding a capacitor will help to produce more a stable control voltage. Good practice is definitely to use the cap. The design I shared use the same Resistor R2 for both charging and discharging the Cap C3. If you search for astable multivibrator using NE555 you can find design using two resistor solutions as well.https://community.element14.com/technologies/555-timers/f/forum/55119/analysis-of-a-555-circuit-design-will-it-work-maybe-there-is-a-better-way/224209Sat, 21 Sep 2024 22:09:00 GMT93d5dcb4-84c2-446f-b2cb-99731719e767:a0ed3c0d-f7af-417d-914f-f7545a8f4986jc2048The constant is ln(2). The 2 comes from the relationship between the switching thresholds. When charging, the lower threshold is twice as far away from VCC as the upper threshold. When discharging, the upper threshold is twice as far away from 0V as the lower one. The natural log is involved because the charging curve is exponential in shape. If you want to delve down further, and work it out from first principles, you'll need to read up about RC time constants, and more generally about circuit analysis.https://community.element14.com/technologies/555-timers/f/forum/55119/analysis-of-a-555-circuit-design-will-it-work-maybe-there-is-a-better-way/224206Sat, 21 Sep 2024 21:04:00 GMT93d5dcb4-84c2-446f-b2cb-99731719e767:b57ad846-2886-4b4b-9e28-443fd5e13276beacon_daveLooks like some have air generators to recharge the battery amongst other tech... https://assets.new.siemens.com/siemens/assets/api/uuid:12efd9a7-8e67-4023-bb3a-61f0e450f90c/sie-bro-end-of-train-brochure.pdf It's gonna be tight to fit all that on a PCB the size of a NE 555 D SMDhttps://community.element14.com/technologies/555-timers/f/forum/55119/analysis-of-a-555-circuit-design-will-it-work-maybe-there-is-a-better-way/224205Sat, 21 Sep 2024 20:59:00 GMT93d5dcb4-84c2-446f-b2cb-99731719e767:a1af61e6-3520-4212-a440-9e66cbed9a32shabazAh, good to see. I watched the first couple. Looks like they exhibit a low duty cycle (or perhaps it changes for different events).https://community.element14.com/technologies/555-timers/f/forum/55119/analysis-of-a-555-circuit-design-will-it-work-maybe-there-is-a-better-way/224204Sat, 21 Sep 2024 20:51:00 GMT93d5dcb4-84c2-446f-b2cb-99731719e767:9cad757a-f9be-4b8e-a77b-83bdee316453Jan CumpsI read the specs, and that's true. They usually run on a battery, and have a light detector to save energy.https://community.element14.com/technologies/555-timers/f/forum/55119/analysis-of-a-555-circuit-design-will-it-work-maybe-there-is-a-better-way/224203Sat, 21 Sep 2024 20:23:00 GMT93d5dcb4-84c2-446f-b2cb-99731719e767:18970667-bcf8-4e78-9271-9ba49fe4c80cbeacon_daveI think there is a photocell that only turns them on in low light https://youtu.be/fE9Y2Pqdwig?t=8 https://youtu.be/LJ_kQLihI3k?t=147 https://youtu.be/d1CnNQ97qKo?t=21 https://www.youtube.com/watch?v=lc_DuOgA5vMhttps://community.element14.com/technologies/555-timers/f/forum/55119/analysis-of-a-555-circuit-design-will-it-work-maybe-there-is-a-better-way/224201Sat, 21 Sep 2024 20:05:00 GMT93d5dcb4-84c2-446f-b2cb-99731719e767:df7c889a-49c7-44a3-be7a-323900893095shabaz(I mean on a real train! : )https://community.element14.com/technologies/555-timers/f/forum/55119/analysis-of-a-555-circuit-design-will-it-work-maybe-there-is-a-better-way/224200Sat, 21 Sep 2024 20:03:00 GMT93d5dcb4-84c2-446f-b2cb-99731719e767:51c68570-18aa-4e4a-9c9a-eb42d804aeebJan CumpsOnce, while driving through Antioch, Illinois, I had to wait for a big looooong freight train to pass by. If only I knew that this device was used then ... It's not used over here.https://community.element14.com/technologies/555-timers/f/forum/55119/analysis-of-a-555-circuit-design-will-it-work-maybe-there-is-a-better-way/224199Sat, 21 Sep 2024 19:56:00 GMT93d5dcb4-84c2-446f-b2cb-99731719e767:1735daea-b018-4102-8fdf-044a3ad489aebeacon_dave[quote userid="123345" url="~/technologies/555-timers/f/forum/55119/analysis-of-a-555-circuit-design-will-it-work-maybe-there-is-a-better-way/224198"]Surprisingly difficult finding a YouTube video showing that device blinking.[/quote] https://youtu.be/SrYin24eBmc?t=411https://community.element14.com/technologies/555-timers/f/forum/55119/analysis-of-a-555-circuit-design-will-it-work-maybe-there-is-a-better-way/224198Sat, 21 Sep 2024 19:50:00 GMT93d5dcb4-84c2-446f-b2cb-99731719e767:624b489d-e070-410a-bfc8-435859ed240fshabazSurprisingly difficult finding a YouTube video showing that device blinking. Watched a couple of instructional videos explaining what it does, and I've learned how to install it howeverhttps://community.element14.com/technologies/555-timers/f/forum/55119/analysis-of-a-555-circuit-design-will-it-work-maybe-there-is-a-better-way/224197Sat, 21 Sep 2024 19:48:00 GMT93d5dcb4-84c2-446f-b2cb-99731719e767:cf26d692-dd1c-4c9a-b9fd-b7484c364d17Jan CumpsI'm an HO fanboy . As child, I had Jouef trains.https://community.element14.com/technologies/555-timers/f/forum/55119/analysis-of-a-555-circuit-design-will-it-work-maybe-there-is-a-better-way/224196Sat, 21 Sep 2024 19:47:00 GMT93d5dcb4-84c2-446f-b2cb-99731719e767:4e60ae98-4c28-4390-9a78-41dcf61fefa5beacon_dave[quote userid="123345" url="~/technologies/555-timers/f/forum/55119/analysis-of-a-555-circuit-design-will-it-work-maybe-there-is-a-better-way/224191"]I suspect train enthusiasts do want it to be close to reality[/quote] The real ones appear to also monitor brake line pressure and use wireless telemetry to send this information back to the lead engine. Oh, and they are battery powered in a self-contained portable unit. I hope this model railroad isn't N-gauge !https://community.element14.com/technologies/555-timers/f/forum/55119/analysis-of-a-555-circuit-design-will-it-work-maybe-there-is-a-better-way/224192Sat, 21 Sep 2024 19:01:00 GMT93d5dcb4-84c2-446f-b2cb-99731719e767:65a9ca06-6206-44a9-9c96-66e1059ecd46Jan CumpsI think that the timings on the schematic are based on the circuit components, not on the regulations of USA train companies.https://community.element14.com/technologies/555-timers/f/forum/55119/analysis-of-a-555-circuit-design-will-it-work-maybe-there-is-a-better-way/224191Sat, 21 Sep 2024 18:54:00 GMT93d5dcb4-84c2-446f-b2cb-99731719e767:a19c6667-b19a-4b60-a062-084f5fb947b6shabazVery useful; indicates that the duty cycle needs to be about 10% at approx. 1 Hz. I suspect train enthusiasts do want it to be close to reality, so that's likely a hard requirement, at least that ballpark anyway.https://community.element14.com/technologies/555-timers/f/forum/55119/analysis-of-a-555-circuit-design-will-it-work-maybe-there-is-a-better-way/224190Sat, 21 Sep 2024 18:48:00 GMT93d5dcb4-84c2-446f-b2cb-99731719e767:80addb8a-f3bd-4759-9adf-b82b152a9486Jan CumpsIf you 'd use dual-side surface mount, this would all fit on a PCB the size of an NE 555 D SMD