Electronic Circuits and Diagram-Electronics Projects and Design

Touch Switch Circuit using NE 555 Description This is the circuit diagram of a small touch plate controller using IC NE 555 .This circuit is ideally useful for making touch operated doorbells, buzzers,toys etc which when touched on the touch plate operates the relay for a preset time and the turns off automatically. This circuit is realized by utilizing the high input impedance of trigger pin of the 555 IC.When  the IC is triggered by the induced voltage of human body the output goes high for a time determined by R1 and C1.The transistor is used to drive the relay.The…

Water Level Indicator Description This is the circuit diagram of a simple corrosion free water level indicator for home and industries. In fact the the level of any conductive non corrosive liquids can be measured using this circuit. The circuit is based on 5 transistor switches. Each transistor is switched on to drive the corresponding LED , when its base is supplied with current through the water through the electrode probes. One electrode probe is (F) with 6V AC is placed at the bottom of tank. Next probes are placed step by step above the bottom probe. When water is…

A Lamp Dimmer/Fan Regulator Circuit We have modified this circuit: – Take a look – Modified Lamp Dimmer Description . This is the circuit diagram of the simplest lamp dimmer or fan regulator.The circuit is based on the principle of power control using a Triac.The circuit works by varying the firing angle of the Triac . Resistors R1 ,R2 and capacitor C2 are associated with this. The firing angle can be varied by varying the value of any of these components. Here R1 is selected as the variable element . By varying the value of R1 the firing angle of…

Fridge Door Alarm Circuit Description. This is a fridge door alarm circuit, which produces an audible alarm when fridge is left open for a preset time. This versatile alarm is based  on two 555 timer IC’s. Both ICs are wired as astable Multivibrators. An LDR is connected in parallel to the timing capacitor C1 of IC 1.When door is completely close there will be no light inside the fridge and LDR offers high resistance keeping R1 fully charged.When door is left open ,the lamp inside the fridge will keep glowing ,LDR will be illuminated, and its resistance falls. This makes…

LED Emergency Light We have developed three circuits under Automatic LED Emergency Light. Two of them are designed by Mr. Seetharaman, a very valuable and important contributor of this website. We have listed the circuits here for your ease of  reading. If you have any doubts; please comment with circuit name or circuit number. 1. Simple Emergency Light using LED 2. Automatic Emergency Light using LM317 IC 3. Modified Version of Automatic LED Emergency Lamp using LM 317   1. Simple Emergency Light Circuit This is one of the most cost effective (cheap) and simple emergency light circuit developed for…