Interfacing 4026 with 7 segment
display
EE158
Group all Htabs Electronics





Description(active tab)
Circuit Diagram
Circuit Diagram 2
Components
Step-By-Step
By:
Anjali Sethiya
CD4026 is a Johnson counter IC commonly used in digital display. It has a 5 stage
Johnson decade counter with a decoder which converts the Johnson code to a 7
segment decoded output. To put it simply, it will convert the input into numeric display
and can be seen on 7 segment display or with LED. It can be used for displaying
analogue value such as temperature with pic microcontroller or for counting objects.
There is various other applications like in 7 segment decimal display circuit, in clocks,
timer etc. Advantages of 4026 counter are: It contains counters and 7 segment
decoded in one package, It can be easily interfaced with 7 segment types, Ideal for low
power display, Operated at wide range of temperature from 5V to 20V and the biggest
advantage of the 4026B counter IC is that it can drive a 7-segment display without
needing a decoder driver IC.
To understand the working of interfacing CD4026 with 7 segment display first we
need to understand its pin diagram.
Now let us understand the working of individual pins-
1. Pin 1 or clock pin- It receives clock signals and at every positive clock, counter
advances one by one. You can provide clock with the switch, 555 timer or with the help
of logic gates. In short high pulse on this input increments the counter.
2. Pin 2 or disable clock (clk inhibit) pin- 4026 counter advances one by one by
receiving positive pulse at this time clock inhibit pin should be grounded. If it is
connected to supply than counter advancement will be inhibited means there will be no
meaning of clock pulse.
3. Pin 3 or enable display (En in) pin- It enable the 7 segment display to display the
numeric value. It should be kept high for enabling the display. Mean output goes high
when only when display enable is high.
4. Pin 4 or enable out- It Enables the carry out pin. In our circuit we have left this pin
unconnected.
5. Pin 5 or divide by 10 output- It is used to complete one cycle for every 10 clock input
cycle and it is also used to cascade more IC's.
6.Pin 6, pin7 and Pin9 to pin 13 - These are 7 decoded output from a to g used to
illuminates the corresponding segment of 7 segment display to display the digit from 0
to 9.
7. Pin 14 or not 2 output (UNGATED "C" SEGMENT) signals- They are not gated by the
Display clock and therefore are available continuously. This feature is a required in
implementation of certain divider function such a as divide by 60 and divide by 12.
8. Pin 15 or Reset pin- It is used to reset the counter. When it receives high it clears the
counter and counting again starts from zero. One important thing about reset pin that it
should be again made low to start the counter once again.
9. Pin 8 or ground pin and Pin 16 or Vdd – It should be connected to power supply.
To understand its working assemble the circuit as shown in circuit diagram 1It uses a 4026 combined counter and display driver IC which is designed to drive 7
segment displays. When you press the switch, counter starts from zero and it advances
one each time whenever pin 1 receives a positive pulse. When you press the switch for
first time numeric 1 will display, on pressing the switch again numeric 2 will display,
giving you second output. In similar manner 3 and 4 will display. And when count
reaches to 9, after that it will again starts it counting from zero.
For resetting the counter to zero, pin 15 must be taken high and then taken low again.
The table shown below shows sequence, how each segment glows after receiving clock
signals?
CMOS IC can switch millions of time in a second. This may cause the switch to deliver
several pulses in rapid succession. But we just want one clock pulse at a time.
Therefore we have used resistor with switches which create a short delay. Hence when
we press switch it will provide high to pin 1 and hold it until switch is again press.
In circuit diagram 2 we have provide the facility to restart the counting from zero from
any point as required by the user. This can be done, just by pressing the Switch S2
momentarily and with the help of Switch S3 you can hold the state of counting. Like you
want number 4 should be displayed on the switch S3, no matter how many times you
press S1 ( Clk input) or S2 (Reset) counter will not start neither it will reset.
/www.engineersgarage.com/electronic-circuits/Interfacing-4026-with-7-segment-display

pressure
General purpose circuit of the simple pressure sensor alarm is built around a couple of readily available
cheap components. Working of this circuit is straight forward and self-explanatory. When the circuit is
powered by a 9V compact battery, the active piezo-sounder at the output of IC1 starts beeping for a short
time and then goes into idle state.
Whenever, the pressure sensor element (Piezo-ceramic wafer) is gently tapped, mosfet T1 is fired by the
electric pulse from the sensor through related components and IC1 is again enabled by T1. As a result, the
piezo-sounder starts beeping for a short duration, set by the in-circuit values of R3 and C2. Piezo-sounder
at the output of IC1 can be replaced with a low current 6 to 9 V electromagnetic/solid-state relay to
control external loads. Likewise, values of components T1,R3 and C2 are not very critical.
You can experiment with another values to “tune” the circuit as per your requirements. Pressure sensors
(in piezo-wafer form) are widely available with reputed hobby electronics components dealers.
Possible Applications of this pressure sensor circuit:
Automatic Door Bell, Carpet Alarm, Hit Switch, Knock Bell, Garage Alarm, Doormat Sensor…
Pressure Sensor Alarm Circuit Schematic
CIRCUIT DIAGRAM
OBJECTIVE : TO CONSTRUCT THE Pressure Sensor Alarm Circuit
APPRATUS REQUIRED : PZ1 – PIEZO WAFER ( PRESSURE SENSOR )
D1- 1N4148
R1- 2M2
R2- 2M2
C1 – 100nF
MOSFET T4 – BS170
C2 – 47Nf
R3 -1M
BATTERY – 9V
IC1 – 555
BZ1 – PEIZO SOUNDER
THEORY: Whenever, the pressure sensor element (Piezo-ceramic wafer) is gently tapped, mosfet T1 is
fired by the electric pulse from the sensor through related components and IC1 is again enabled by T1. As
a result, the piezo-sounder starts beeping for a short duration, set by the in-circuit values of R3 and C2.
Piezo-sounder at the output of IC1 can be replaced with a low current 6 to 9 V electromagnetic/solid-state
relay to control external loads. Likewise, values of components T1,R3 and C2 are not very critical.
Possible Applications of this pressure sensor circuit:
Automatic Door Bell, Carpet Alarm, Hit Switch, Knock Bell, Garage Alarm, Doormat Sensor…
CAPACITORS UNIT CONVERSION: -
1pf = .001 nf =0.000001mf =0f.
1uf=1000nf=1000000pf=0.000001f .
1nf=.001uf=1000pf=1e-9f.
1f=1000000000000pf=1000000uf=1000000000nf.
General purpose circuit of the simple pressure sensor alarm is built around a couple of readily
available cheap components. Working of this circuit is straight forward and self-explanatory.
When the circuit is powered by a 9V compact battery, the active piezo-sounder at the output of
IC1 starts beeping for a short time and then goes into idle state.