Category: 555 Timer Projects

Here is a simple circuit mains box heat monitor for sensing high temperature due to overheating. This circuit helps to prevent disasters caused by only sparking in the mains box due to any fault as a short circuit overloaded. This circuit is so designed that it also automatically switches on a bright white LED (LED3) in case of power failure. This light is sufficient to check the mains box wring or fuses in darkness. Circuit Description Mains Box Heat Monitor The circuit is built around a timer IC, a sensor,…

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There are many display circuits already published in BEP. But the circuit Running and Spellar Effects of Light Circuit is very special in its own way because it contains all the facilities required for any type of decoration. Lighting decoration broadly consists of two main categories-the running effect and the spellar effects. Running effect is well known to every electronics hobbyist. The spellar effect consists of many output driving the load-lamps; all of them go high one after another, and eventually all outputs becomes high simultaneously showing a complete display.…

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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…

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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…

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Most common stereo cassette players have an auto-stop deck mechanism but do not have the auto power-off function. The circuit is meant for cassette players having an operational voltage of 12 V DC with the facility of LED type VU meter. When the sound signal stops, the power is automatically switched off after a delay of approximately 30 seconds. Circuit Description of Auto-off Cassette players With sound present, the LEDs of VU meter emits light. The LDR on receiving light from LEDs gives a high pulse to transistor T1which charge…

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