Binary Coded Decimal is a number system that only counts from 0 to 9 and then repeats. The table below shows the conversion between the different numbering systems and BCD code. BCD is also called 8421 because the binary LSB counts as a 1, the next bit adds....

I have it set up so that I get an out put signal that goes High for about 1/2 second, and then goes low for about 1.33 seconds. The problem is that....

This egg timer, which is both simple and functional, shows once again that it is not essential to use a microcontroller for everything these days. The circuit consists of only two ICs from the standard 4000 logic family, a multi-position rotary switch and a....

An Intergrated ircuit is just that. an intergrated circuit. These small packages combine many individual components to perform a specific function. They vary in shape and size depending on their complexity. They are categorised into functions like Audio,....

Clock timer uses a PIC16F628 microcontroller to display 3 and 1/2 digit time and control an external load. The clock includes a calendar with leap year and optional daylight savings adjustments. The timer output can be set from 1 to 59 minutes and manually....

With the help of high gain high impedance operational amplifier, we can build a long time delay with resistor-capacitor (RC) circuit since it allow high....

Class D amplifier for ATtiny15L microcontroller circuit diagram. These units can get acquainted with one embodiment of the amplifier is Class D. Controller ATtiny15L AVR family firm Atmel is perfectly suited for this purpose, because it contains a ten-digit....

This page identifies all the hardware modifications necessary to adapt a Kenwood TK-931 transceiver for operation as a 2 watt exciter for 927 MHz repeater service. Not shown here is the effort required to program the radio for the desired operating....

..

The following circuit shows about Alarms Police / Ambulance electronic Diagram Design. Features: simple and easy to assemble, Cheap circuit, ....

When ever you need to get an alarm or intimation after ten minutes, the circuit shown below can be used. The circuit is nothing but a monostable multivibrator based on IC NE 555. When ever you press the reset push button the green LED D1 glows after 10....

This system is a Drag Race timing system centered around a micro-controller. The system consists of the Christmas Tree (the three yellows, the green and red lights), the fault sensor (checks to see if a racer started racing before the green light), the....

THE circuit shown provides a smooth, piercing, wailing siren with a minimum of components. Not only this, but three spare gates of hex inverter IC1 remain, which means that a true cacophony could be created by running two sirens off the same i. c. Gate IC1a....

With an NE555 you are also able to build an astable multivibrator or blinker. Find out how, and what you need to be aware of....

So here is another improvised model circuit that will eliminate the unwanted DC offset voltage from the output that affect the previous one discussed. By the way, all previous circuits that I discussed were intended as low power  class d amp source that is....

..

This 12V power inverter circuit can be used to power small power devices that need a 240 volts. This 12V power inverter circuit is very useful when you want to use a 240 volts consumer powered by a 12 volts car battery. In contrast to the usual feedback....

This circuit provides a visual 9 second delay using a 7 segment digital readout LED. When the switch is closed, the CD4010 up/down counter is preset to 9 and the 555 timer is disabled with the output held high. When the switch is opened, the timer produces....

It allow your car headlights to flash on and off at the same time or it will cause them to flash alternately. Component: 555IC, Transistor, Resistor, Relay, Polarised Capacitor...

Herein is the scematic picture of 9-Pin RS232 Line Booster Signal Direction. This device is a 9-pin RS-232 repeater that re-transmits all 8 signals and carries the ground line through..

A very simple Ionization Smoke Detector with Interconnect and Timer alarm circuit can be constructed using the A5367 low-current, CMOS circuit that provides all of the required features for an ionization-type smoke detector. A very nice thing at this....

Fridge Door Alarm circuit or a Refrigerator door open alarm using 555 Timer IC, which produces an audible alarm if the door left open for a preset time....

The adjustment control for the contrast of an LC-Display is typically a 10-k potentiometer. This works fine, provided that the power supply voltage is constant. If this is not the case (for example, with a battery power supply) then the potentiometer has to....

The circuit is a basic 555 timer circuit in astable mode. In this configuration the IC sends a brief pulse to the buzzer every few minutes. The values....

the timer will generate the basic period (for example 20ms) and with some associated variables will be possible to "fire" an I/O pin to generate the signal. For example, using a 8 bit variable, we can divide the generated frequency in "chunks" of 256 (8 bit....

This voltage doubler circuit use a 555 timer integrated circuit wired as an astable mutivibrator. This voltage doubler circuit can deliver only up to 50mA output current and above that current limit the output voltage will be reduced. The actual output....

..

This is a continuation of my previous article regarding class d amp using 555 timer chip. Looking back to several schematics on that article, some of you may wonder why I include another 555 as U2 in the drawing. The main purpose of this U2 is to establish....

The IR detector (IC3) controls an LM 7555 CMOS timer (IC2) which operates in mono stable mode. When the beam is broken, IC2 is triggered and its pin 3 output goes high for about half a second. This extinguishes LED1 and turns on transistor Q1 to drive a 5V....

We know that microcontroller is an integrated chip which consists of RAM, ROM, CPU, TIMERS, COUNTERS etc. PIC is a microcontroller which also consists of RAM, ROM, CPU, timers, counter, ADC (analog to digital converters), DAC (digital to analog..

This timer was designed for people wanting to get tanned but at the same time wishing to avoid an excessive exposure to sunlight. A Rotary Switch sets the timer according to six classified Photo-types (see table). A Photo resistor extends the preset time....

This circuit uses a Cmos 4017 decade counter to create a sequence of four separate events. The number of events in the sequence may be increased to nine or ten. And the length of each event is controlled independently. D13 causes the sequence to repeat....