LED Running lights CD4017

This is a Gadget Tutorial for this Article LED Running lights CD4017 – Live Gadget Page.

Red Button Powers LED Running Lights, 555 Clock is counted by CD4017. Adjust R2, See ToolTips. This Demo shows LM555 running a CD4017 Counter to drive Ten Leds sequentially.

Press the Red button below to turn on the circuit press it again to turn off, i have put a new battery and did the wiring for you. The Red LED will flash according to the state of the 555 output at pin 3. The decade counter-divider CD4017 has 10 outputs, for every low to high transition, rising edge, the counter advances one LED. After going one full circle the the first LED lights again and it goes on…..

LED Running lights CD4017

The 10 outputs have 10 green LEDs. The current thru the LED is limited by R1, the current can be calculated like this (9V – 1.6V) / 1K = 7.4mA this is within 20mA which is the danger limit of the CMOS output. You want it to be bright use transistors for every output.


LM311 – Voltage Comparator

The LM111, LM211 and LM311 are voltage comparators that have input currents nearly a thousand times lower than devices like the LM106 or LM710. They are also designed to operate over a wider range of supply voltages: from standard ±15V op amp supplies down to the single 5V supply used for IC logic.

LM311 – Voltage Comparator

LM311 - Voltage Comparator

Both the inputs and the outputs of the LM111, LM211 or the LM311 can be isolated from system ground, and the output can drive loads referred to ground, the positive supply or the negative supply. Offset balancing and strobe capability are provided and outputs can be wire ORed.

  • Operates from single 5V supply
  • Input current: 150 nA max. over temperature
  • Offset current: 20 nA max. over temperature
  • Differential input voltage range: ±30V
  • Power consumption: 135 mW at ±15V

Related Resources –

Voltage Comparator Information And Circuits

This page provides basic information about voltage comparator integrated circuits and is to act as reference material for other circuits. The circuits shown are based on the LM339 Quad Voltage Comparator chip or the LM393 Dual Voltage Comparator chip. These devices are functionally the same. The LM311 Voltage Comparator can be used for these applications as well but it also has a number of unique features.

Comparators and Schmitt Triggers

An LM311 in a comparator circuit is shown at the right, with the pin numbers for the connections. The open-collector output is at pin 7, and the ground for this transistor is at pin 1. It is shown pulled up to the logic voltage of +5 with a 1k resistor, which is typical. The output of the LM311 can sink 8 mA. A comparator’s output is essentially binary, YES or NO.

Control system design Notes

Proportional Controllers not only save energy, they can give a controlled finish or treatment to a job. An on-off controller or thermostat limit protection has to be used in series, this is to to stop a Runaway Process.

control system design

There was a real life instance when a Temperature cycling oven maker (environment chamber), faced large liabilities as an 8086 based profile controller and chart recorder just locked up and all the electronic equipment were roasted. Here even a bimetallic thermostat would have saved the day. Nowadays we have a watchdog timer to prevent such uP mishaps, but still use an analog controller in series as an over temperature trip.

Other Reading

The basics of control system design: Part 1 – Moving beyond PID

“This series of six articles will explore the use of six variations of P, I, and D gains: Proportional Control, Proportional-Integral Control, Psueodo-derivative feedback with feed-forwared (PDFF), PID control, PID+ control, and Proportional Derivative Control.”