The objective of this construction project is to build a simple and easy to use Opamp Tester. This test gadget can be used to test the popular general purpose opamp type 741 and other such opamps that are pin to pin compatible to 741.These include the opamp type numbers much as LM 709, LM 201, [...]

The objective of this construction project is to build simple and easy to use test gadget that can be used to identify good and bad IC TIMERS from a given lot. Like opamps, an IC timer is another widely used electronic device and it finds its place in almost every project of hobbyists’ interest. This gadget not only enables you test the IC timer 555, it will also give you an opportunity to appreciate the tremendous functional potential of the various terminals of this truly versatile IC. Most of the circuits appearing in various magazines or books to test IC timers do the same by wiring the IC in one particular configuration only. Testing the IC timer with the gadget being described here not only tests the IC in all basic configurations, it practically tests the functionality of read more

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Thyristors (SCRs, Triacs) are very popular in AC power control applications where they are used to provide an active control of the AC power being fed to the load. The load here could be anything that is operated from AC mains and whose parameter to be controlled happens to depend upon the amount of AC power. Speed of motors, Temperature of heating elements etc are some of the examples. Here, we would build a simple circuit to demonstrate separately the use of SCRs and Triacs to provide AC power control. SCRs are used for those loads where it is immaterial whether the load current is unidirectional or bidirectional (though the AC input is always bidirectional). Heating element is one such load, an incandescent bulb is another. Remember that amount of heat is always proportional to read more

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Under previous posts, we have already seen how a bipolar transistor, NPN or PNP, can be used as a single pole, single throw switch. The transistor operating in saturation region with voltage across the switch being about 0.2 volt represents the ON-condition of the switch. The transistor operating in the cut-off region, where the only current that can flow through the switch is the collector-to-emitter leakage current represents the OFF-condition of the switch. We also demonstrated how an SCR can be used as a single pole single throw switch of the latching type. Another very important solid state device that can be usd as a switch in a way similar to the operation of a bipolar transistor is the Metal Oxide Semiconductor Field Effect Transistor (MOSFET) briefly mentioned in the last read more

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The objective of this simple exercise is to demonstrate the operation of solid state (or electronic) switches using electronic devices like TRANSISTORS or SCRs. There are many more electronic devices that can be used for the purpose. We have chosen these two as these are the most commonly used ones in this role, more so in the electronics circuits of hobbyists’ interest. MOSFET (Metal Oxide Semiconductor Field Effect Transistor) is another commonly used switching device that has outclassed bipolar junction transistors in many switching applications. It is not covered here but is separately covered in the next project. CIRCUIT DESCRIPTION The first part of the circuit starting from extreme left and comprising of Resistors R1, R2, Switch SW1, LED-1 and Transistor Q1 illustrates the read more

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