Solar cell is the semiconductor device that converts light energy into electrical energy through the Photovoltaic effect. Solar cells are intended to capture energy from the sunlight while the term Photovoltaic cell is used to denote the devices that receive light from unspecified sources. Solar cells are connected in series to get Additive voltage. The serially connected solar cells are encapsulated as Modules which are then interconnected in series or parallel to get a large Array. Series connection increases the voltage while parallel connection increases the current. Each panel has specified voltage, current and power output which depends on the number of solar cells connected in series and parallel. Let us see some solar facts.
Design of the popular Timer IC 555 is so interesting and this tiny chip can be exploited in various ways to make different types of circuits. It can be a Monostable, Astable, Bistable, Toggle, Schmitt trigger etc. The Schmitt trigger action is achieved by exploiting the activities of its two internal comparators. Let us make an Automatic Porch light using the Schmitt trigger property of IC 555. It is an ideal circuit to light the premises of home even if the inmates are not there.
Voice Recording chips are now available to record voice and sounds and to play it for a short time. These chips are ideal for the gadgets like Toys, Door phone, Alarms, Automatic answering machines etc. These chips have a recording memory from 20 to 60 seconds and the memory lasts for many years if the chip is properly maintained. The advantage of the chip is that, it requires no software and microcontroller for its operation. Let us build this tiny voice recorder.
A short range Radio Remote system can be implemented using the VHF radio remote control modules VG40 T and VG40 R. These are compact sealed VHF Transmitter and Receiver module pair works without antenna. Its range is 15-20 meters. These modules find various applications in Wireless door chime, Toy controlling, Security system etc. Here explains the design of an Appliance On / Off switch using the radio waves.
Again another Johnson counter IC for digital display. CD4033 is the 5 stage Johnson Decade counter with Decoder. The output decoder converts the Johnson code to a Seven segment decoded output which can drive LED or 7 segment display in numerical values. This IC is widely used in 7 Segment decimal display circuits, Frequency division 7 segment displays, Clocks, Timers etc. Let us see it’s is working and the circuits.
The Frequency Modulation (FM) system conveys information over a carrier wave by varying its frequency. The broadcast band of FM falls within the VHF part of the Radio spectrum. Usually 87.5 – 108.0 MHz is used to transmit and receive the FM signals. See the important aspects of FM transmission and the Design of an FM transmitter using IC UPA 1651.
IC 4017 is the 5 stage Johnson Decade counter IC widely used in chaser lighting circuits. It takes the clock pulses from the Clock input and makes one of the ten outputs On in sequence each time a Clock pulse arrives. A Johnson counter, also called Walking ring counter is the modified Ring counter in which the last stage is Inverted and fed back as the input to the first stage. It is a Decade counter since the counting is in Decimal digits and not in Binary. See the working details of CD 4017 and the Circuits.