Nowadays, commercially available washing machines are provided with features like the auto-off timer, reversible impeller, etc. Most of them have mechanical timers, reverses, etc. Some are equipped with electronic timers. But they are very expensive and out of reach of the average consumer. Electronic Washing Machine Control circuit provides all the facilities provided by reputed companies and even more. The circuit has a timer circuit that can be set to any duration from 0 to 15 minutes and can be extended to any length of time by merely changing a…
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Transformer Test Circuit to Overcome Line Voltage Variation
One of the initial production tests carried out on power transformers used in electronic equipment is the measurement of on-load voltages across their secondary windings. During this test, the basic requirement is that the voltage across the primary winding is maintained at the rated line voltage. But in practice, there will be variations in the line voltage and its effect will be reflected on the secondary side. Hence the test carried out will have their internal error. Circuit Description of Transformer test circuit to overcome line voltage variation Here is a…
Read MoreTen Channel Sequential Lighting Circuit
The project Ten channel Sequential Lighting presented here gives a flashing light effect from left to right and then from right to left. IC1 (NE555) generates clock pulses for IC2. The output using rectifiers produce the effect of bulbs flashing from left to right. As the carry output pin 12 of IC2 is connected to the clock input of IC3, the bulbs which are connected to IC5 also starts flashing from right to left. As these outputs are not capable of handling large currents, they have to be amplified to…
Read MoreDynamic Display Ads Circuit
This project of “Dynamic Display Ads Circuit” is based on serial input and parallel output sift register 74164. With the help of the project dynamic display ads circuit we can build a display board, where LEDs blink to give a running light effect. Circuit Description of Dynamic Display Ads Circuit The project dynamic display ads circuit may be used to advertise or display of name plates etc. It is made versatile by using the 555 and 74 series of ICs, which are readily available in the market. In the dynamic…
Read MoreFuzz effect box for Guitarists
The ‘fuzz’ sound is derived by clipping the input waveform, thereby enriching the signal with odd harmonic which provide the hash sound. This circuit “Fuzz Effect Box for Guitarists” is a basic project produces a fuzz which gradually decays into a ‘clean signal’. Circuit Description of Fuzz Effect Box for Guitarists The circuit uses the standard op-amp 741 in non-inverting configuration. The gain of this amplifier is controlled by the feedback network comprising VR1, R2 and R3. Input signal from the guitar passes to the op-amp through DC blocking capacitors…
Read MorePocket Radio Using LA4510
Here is a circuit for a pocket radio using one IC LA4510 and three transistors. This circuit differs from ordinary circuits at the audio stage only. Here a small 9-pin IC LA4510 is used. It replaces three transistors, a driver transformer, and many other passive components. The amplifier circuit needs only one resistor! At zero signal level, this circuit draws 8-10 mA current only. With a 3-volt supply, this circuit can give 200 mW output power. For making this radio you may buy an ordinary pocket radio PCB and assemble…
Read MoreMini Emergency Light Circuit
There are various type of emergency light circuits. Every circuit has its own importance and utility. But size, cost and efficiency of the circuit are some of the main feature of interest. A very simple circuit of mini emergency light is given here. In normal daylight or electric light, the LDR offer very low resistance. So the positive voltage is applied to the base of transistor T1, making it reverse biased. Therefore, T1 does not conduct in presence of light. As transistor T2 also is reverse biased it does not…
Read MoreAutomatic Cut off Power Supply
We are aware that when the line voltage becomes more than 250 volts and less than 160 volts, it can damage our TV sets, refrigerators, etc. Hence, we use voltage stabilizers which are costly. The circuit Automatic Cut-off Power Supply described here is low-cost. The assembling cost comes to around $1 only. If the voltage exceeds the mentioned range it automatically cuts off the supply so that the life of the TV set and other devices can be extended. Circuit Description of Automatic Cut off Power Supply The common point of…
Read MoreAutomatic Time Indicator for Telephone
The circuit Automatic Time Indicator for Telephone presented here provides an audible warning 2.5 minutes after dialing the telephone. The circuit does not make use of telephone line for its operation. Circuit Description of Automatic Time Indicator for Telephone The circuit consists of three 555 ICs. It can be divided into three parts- touch switch using IC1, timer using IC2 and oscillator using IC3. The on touch plate is in the form of a wire, the insulation of which is attached to the stopper on the telephone dial. The off touch…
Read MoreElectronic Ballast Circuit
The fluorescent tube-light requires additional gear such as the copper ballast and starter for normal operation. These two are required to provide the initial high voltage for ionization and thereafter to limit the current through the tube to safe values. It has been observed that the illumination efficiency of the tube-light when excited by high frequency power source is higher than that when excited at the 50Hz line frequency. Moreover, the power factor and the efficiency of the bulky copper ballasts are poor. Hence, electronic ballasts circuit were developed to…
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