Battery Status Indicator. Design Trick 17

You can add this Simple Battery Monitor to Inverter circuit or Emergency Lamp circuit to indicate the level of battery. It can be used to monitor 6 volt or 12 volt battery. Two LED indicators are provided. Green LED lights, if the battery voltage is higher than the set level and Red LED lights when the battery voltage drops below the set level.

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Timer Relay. Design Trick 16

You can make this Transistor timer easily for driving a relay for few seconds to few minutes. It is too simple and uses only two transistors and few other passive components. Just press on the switch to start relay and after the time ends, relay will switch off. You can also set the time using a Trimpot.

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Familiarize Electronic Components Part II – Transistors

This section describes the features of Transistors, their working and Pin identification methods.

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Know the meaning of Transistor and IC Codes

Transistors and ICs are coded so as to identify its semiconductor, use, type, make etc. By using the codes, it is easy to select the appropriate component for the circuit. See the meaning of these codes.

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Heat Sensor

This simple circuit acts as a warning device whenever the temperature exceeds the preset level in its vicinity. It is an ideal circuit to monitor the heat generating devices like PC, Inverter etc.

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Unusual LED Indicator

Here is an Unusual LED indicator for the Battery. It turns on fully when the battery voltage is above 13 volts and starts to blink faintly when the voltage drops below 12 volts .Finally the LED turns off  when the voltage drops below 10 volts. Its design is unusual because the LED driver transistor is connected in an unusual way.

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