Digital & Analog Based Mini electronics Projects Page_4

Digital & Analog Based Mini electronics Projects Page_4

31. Digital Switching System:

This circuit can control any one out of 16 devices with the help of two push-to-on switches. An up/down counters acts as a master-controller for the system. A visual indication in the form of LEDs is also available.

32. Digital Timer Enhancement:

This simple circuit automatically activates or deactivates an electronic device at the time of alarm preset in a clock. When the alarm rings, the tone burst generated at the terminal of the buzzer triggers the circuit and the relay energizes or de-energizes to switch on or switch off the load.

33. Drinking Water Alarm:

The State Jal Boards supply water for limited duration in a day. Time of water supply is

Decided by the management and the public does not know the same. In such a situation, this water alarm circuit will save the people from long wait as it will inform them as soon as the water supply starts.

34. Dual Supply From Single Battery Source:

Dual-voltage power supply is required especially for powering the op-amps and some of the instrumentation amplifiers. A few low-power audio pre-amplifiers also use dual-voltage supply.

35. Economical Pump Controller:

The automatic pump controller eliminates the need for any manual switching of pumps installed for the purpose of pumping water from a reservoir to an overhead tank.

36. Electronic Candles:

Here is a simple circuit that can produce the effect of candle light in a normal electric bulb. A candle light, as we all know, resembles a randomly flickering light. So, the objective of this project activity is to produce a randomly flickering light effect in an electric bulb.

37. Electronic Card Lock:

The circuit presented here can be used as a lock for important electronic/electrical appliances. When card is inserted inside its mechanism, depending upon the position of

Punched hole on the card, a particular appliance would be switched on. The card is inserted just like a floppy disk inside the disk drive. This card should be rectangular in shape with only one punched hole on it.

38. Electronic Motor Starter:

This motor starter protects single-phase motors against voltage fluctuations and overloading. Its salient feature is a soft on/off electronic switch for easy operation.

39. Electronic Quiz Contests:

This jam circuit can be used in quiz contests wherein any participant who presses his button (switch) before the other contestants, gets the first chance to answer a question. The circuit given here permits up to eight contestants with each one allotted a distinct number (1 to 8). The display will show the number of the contestant pressing his button before the others. Simultaneously, a buzzer will also sound. Both, the display as well as the buzzer has to be reset manually using a common reset switch.

40. Electronic Quiz Table:

Here is a simple, low-cost quiz table for four game participants. It determines the contestant who first presses the switch (S1 through S4) to answer a question and locks out the remaining three entries. Simultaneously, the respective audio alarm sounds and the bulb glows. The quiz table can be used for more number of contestants simply by adding buzzers, bulbs, MOSFETs and diodes. Besides, it provides an option for varying the time for which an individual buzzer and the corresponding bulb should be ‘on’ after a particular competitor has pressed the pushbutton. These timings can be set by presets VR1 through VR4 as required.