LED Flasher Circuit with Counter

Electronic students or hobbyists always like to make various circuits for their homes or schools, and especially light flashing circuits, and there are many circuits and kits on the market that can turn on any number of LEDs or lights periodically, randomly or sequencially. A versatile integrated dual surge counter that can be used to make a simple LED flasher circuit.

As we explained in the counters training, surge counters are basically flip-flops that can be used as frequency dividers to divide the reference clock input into a certain amount to give a new, lower frequency, and which we can use as part of our simple work.

Such counters are inherently asynchronous because not all flip-flops change or "switch" with the application of an external clock pulse. Typically, the transition occurs on the negative edge of the clock pulse.

Switching or "T-type" flip-flop is the basic building block of all counters with asynchronous counters, since the input clock pulse appears to "fluctuate" along the counter, often referred to as "surge counters". It is produced from the output of the previous stage. The result is a ripple effect, as each stage changes sequencing, and we can use it directly as a simple LED flasher circuit.

A series of 2 splits that cascade together to create a single N-dividing frequency divider, where the surge counter is equal to the number of counter bits of N, is generated from T-type flip-flops. Common binary surge counter integrations include 74LS93 4-bit (÷16), CMOS 4024 7-bit (÷128), CMOS 4040 12-bit (÷4096) or larger CMOS 4060 14-bit (÷16,384).

The output numbers (Qn) will then be defined as the "N-pearl" stage of the counter. For example, Q6 output is 26 = 64(1/64thof the clock frequency) and Q12 212 = 4096 (1/4096 of the clock frequency) and so on.

As we can see, there are many binary counters that can turn on any number of lights periodically, randomly or sequencially, but there is a versatile integrated that hobby or student can use to produce a simple LED flasher for use on various different lighting screens. CMOS CD4040B is a 12-bit Binary Counter.

Cd4040B is a fast switching 12-bit binary surge counter with twelve fully resolved outputs (creating a total of 12 separate LED arrays). These twelve outputs change sequentially each time a negative outbound edge of the clock pulse produces a binary output array, as shown in the schedule diagram.

The outputs of the 4040 switch between logical "1" and logical "0" at each count, so that a moving array can produce a following or random effect, making the 4040 ideal for a simple LED flasher.

Because 4040 is a 12-bit surge counter, each of the twelve outputs will switch between HIGH or LOW in a binary order from 0 to 4096(2 12),and this is shown in the schedule diagram below.

led flasher with counter
4040 Ripple Counter Schedule

But before using the 4040B surge counter as part of our simple LED flasher circuit, we need to produce a timing signal. There are many different ways to generate a timing or time signal, the list is endless. However, a very simple and effective way to generate a frame wave timing signal with the minimum component is to use a special timing integration, such as the NE555 Unstable Timer.

Writing Suggestion

We recommend that you read the content we have created about the 555 Integration.

The timing period T depends on the selected input time frequency, a small reminder: T = 1/ε. For example, if we select the 4040 12-bit (÷4096) counter as part of our simple LED flasher circuit and want our longest timing time over 12.-bit to be 4 seconds (2 seconds ON and 2 seconds OFF), or if we want 0.25Hz, then the 4040 counter must be approximately 1kHz (0.25 x 4096), as shown by our input clock frequency on pin 10.

Simple LED Flasher Circuit

led flasher with counter

By connecting the LEDs to different outputs, we can burn and flash them one by one, but they flash to each other at different rates (each output is half the frequency of the previous one), and not all of them will be "ON" or all "OFF", which helps us to use LEDs as flashers.

Using frequency dividers/counters divided by 2 with multiple LEDs connected to their output, it is possible to produce a glowing star or flashing light effect or any LED flashing light image you want, depending on which surge output you connect the LEDs to. Physical placement is very important in order to achieve satisfactory results as an image.

Surge Counter Output

Q1 to Q12 meter outputs can meet a load current of up to a maximum of 15mA, which is sufficient to drive LEDs directly. The fact that the 4040 counter has both "Sink" and "Source" (feed) current means that leds can be connected between the signal terminal and the feed of the numberor, or between the signal and the output terminal to absorb the load current.

Absorbing and Sourcing Outputs

led flasher with counter led flasher with counter

In the first circuit above, the LED positive feed rail ( +Vcc ) depends on the Q8 output. In this case, the LED will be "ON" when the output is "LOW" as the current will "Fall" (absorb) or flow into the Q8 output terminal of the number 4040.

The second circuit above indicates that the LED is connected between the output, Q8 and soil (0v). This will be the LED's "ON" when the output is "HIGH", as the current will flow out of the "Source" (feed) or 4040 counter output terminal.

The ability of the surge counter to both absorb and weld the output load current means that both LEDs can be connected to a single output terminal, increasing the number of LEDs we can use in our simple LED flasher circuit. However, depending on whether the output status is "HIGH" or "LOW", only one LED will become "ON" at any time.

The circuit in the third image shows an example of this. The two LEDs will be alternately switched to "ON" and "OFF", depending on the output that creates an alternative flashing action. Serial resistors can be used if necessary to limit led current to less than 15mA.

We have previously said that the maximum output current to reduce or weld the load current through the output pins is about 15mA, and this value is more than enough to drive or replace LEDs or small lamps, etc. Instead of this simple LED flasher, we can control higher-power devices such as motors, electromagnets or relays. But then we will have to use a transistor to drive the load and provide a sufficiently high current.

Driving a Transistor with a Surge Counter

led flasher with counter

The transistor in the two examples above can be replaced with a Power MOSFET (Power MOSFET) integration or Darlington transistors if the load current is high. When using an inductive load, such as an engine, relay or electromagnet, it is advisable to connect a flayback diode directly to the load terminals to absorb any back emf voltage produced by the inductive device when the situation changes.

It is also possible to add more LEDs to the output, but keep in mind that it usually requires about 15 to 20mA at 1.2V for each LED to burn precisely, so keep this in mind when connecting the circuit to a battery or power supply. One advantage of the 4040 integration is that it self-limits the maximum input/output current so that leDs can be connected directly without the need for any current limiting resistance.

We found that we could create a very simple LED flasher circuit using a CMOS 4040 12-bit Asynchronous Surge Counter to interface with NE555 Timer and LEDs to create only a widely available component, timing time signal. Since the simplest LED flasher circuit is naturally suitable for the application of the transition feature counting process, it can only be created using a one-bit T-type flip-flop if necessary.

Multi-bit surge counters can be cascaded together to produce larger bit surge counters (or counters) that you select, or decoded to reset after a specific binary count. The 4060B is a 14-bit dual surge counter with its own built-in oscillator circuit, so by adding only one timing capacitor and two resistors, a very simple LED flasher circuit can be created without the need for an additional NE555 timing circuit.