Category: Switching and Controlling

The circuit described here is a Priority Lamp Circuit which gives priority in switching. Switches SW1 to SW4 is a push-to-off type or push-button type, as desired. Normally, pushing off any switch will turn ‘on’ the corresponding relay, i.e. pushing of SW1 enables the NPN transistor T1, and hence relay RL1 operates. The logic section of is designed to get a controlled high output. The pressing of one switch disables the operation of all switches and results in priority in switching. In normal cases, all switches are closed and all relays…

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This project “Staircase Light  Switch Circuit” may be used where it is necessary to control a single light or device by switches situated at different places. The control of a staircase light switch circuit is one of the applications of a light switch circuit. Staircase Light switch circuit can also be used to control an outdoor light using switches situated both inside and outside of the house. Any number of switches may be connected to the light switch circuit. As the switches are wired in parallel, the wiring can be…

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Temperature-controlled soldering stations are now readily available in the market. Such instruments use thermocouples or thermistors as temperature sensors. But even if it’s available in markets it’s fun and experience to build this device yourself.  An electronics hobbyist would surely like to build this unit to enhance the working life of his soldering iron bit and to save power. With a basic knowledge of comparators, this circuit “Temperature controlled soldering iron station” is very easy to understand. Transistor T1 BC107 is used here as a temperature sensor. The fact that…

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