Reverse engineering the popular 555 timer chip (CMOS version)

This article explains how the LMC555 timer chip works, from the tiny transistors and resistors on the silicon chip, to the functional units such as comparators and current mirrors that make it work. The popular 555 timer integrated circuit is said to be the world's best-selling integrated circuit with billions sold since it was designed in 1970 by analog IC wizard Hans Camenzind[1]. The LMC555 is a low-powe ...

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Programmable digital timer switch using a PIC Microcontroller

Digital timer switches are used to control the operation of electrical devices based on a programmed schedule. This project describes a programmable digital timer based on the PIC16F628A microcontroller that can be programmed to schedule the on and off operation of an electrical appliance. The appliance is controlled through a relay switch. This timer switch allows you to set both on and off time. That mean ...

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PIC16F628A Programmable Digital Timer

Programmable relays find use in numerous automation applications such as automatic street light control, watering and pump control, HVAC, home automation, power plants automation in industries, etc. This article describes how to build a fully functional, one-channel programmable relay switch using the PIC16F628A microcontroller. It allows you to set both ON and OFF time. The maximum time interval that you c ...

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00 to 99 minute timer using PIC16F628A microcontroller

Last week I was browsing my old backup hard drive and I found a source code for a very simple PIC based digital timer that I made a couple of years ago. The actual hardware of the project isn’t with me anymore. I might have lost it when I moved from my old apartment into my new home. However, I thought this might be a good practice project for beginners and so I am sharing it here. I am not going to build i ...

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Reverse engineering the popular 555 timer chip (CMOS version)

This article explains how the LMC555 timer chip works, from the tiny transistors and resistors on the silicon chip, to the functional units such as comparators and current mirrors that make it work. The popular 555 timer integrated circuit is said to be the world's best-selling integrated circuit with billions sold since it was designed in 1970 by analog IC wizard Hans Camenzind[1]. The LMC555 is a low-powe ...

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2-Wire Keypad Interface Using a 555 Timer using PIC16F628A

Keypads are a very commonly used input device in microcontroller-based systems. In a keypad, multiple switches are arranged in rows and columns so that they could be interfaced to a microcontroller with a minimum number of I/O pins. For example, a 12-key keypad is arranged in a 4×3 format, which allows to interface the 12 keys to a microcontroller with only 7 connections. The location of each key on the key ...

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2 Digit 99 Seconds Timer

2 Digit Count Down Timer is a utility Count Down timer project for upto 99 seconds of countdown time.  This project can find many uses in your shack and home.  The relay output remains on during the Count Down period, allowing you to interface load or alarm that you want to keep it on for a certain amount of time (in seconds). Specifications Microcontroller based design for greater accuracy and control Powe ...

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555 timer teardown: inside the world’s most popular IC

If you've played around with electronic circuits, you probably know[1] the 555 timer integrated circuit, said to be the world's best-selling integrated circuit with billions sold. Designed by analog IC wizard Hans Camenzind[2] in 1970, the 555 has been called one of the greatest chips of all time with whole books devoted to 555 timer circuits. Given the popularity of the 555 timer, I thought it would be int ...

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PIC 18F4550 Timer And Interrupt Example Video Project

Welcome back everybody! This video covers multitasking via timers and interrupts with the PIC 18F4550. A few notes on this video: -To keep the pace of the video going I added fast forwarding more than in the previous videos. Please let me know in the comments if this was helpful or better compared to the previous videos with less fast forwarding. -I recorded a substantial part of this video, especially the ...

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Long Period Astable Timer using PIC12F629

Description This software functions as a long period astable mutivibrator.  The mark and space period can be set from 1 second up to a maximum 65535 seconds (18h12m15s). Using the internal 4Mhz RC oscillator delays with an accuracy of 99% or better can be achieved  The code also implements an edge triggered reset and an active low hold function.  The reset edge can be configured for rising or falling edge.  ...

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