Ideas on Building Sensitive Voltage Detector


In order to make a sensitive voltage detector, you can simply make use of one to three transistors made of semiconductors that would be able to amplify voltages and currents. A single transistors would be able to amplify at least hundreds times of electrical signals. The amount of amplification is also known as the gain. As for the antenna, you only need to use a copper strip that comes with a voltage which is equivalent to 6V or 9V. The circuit that you have created can be tested on a solder less breadboard before you finally solder all of the components together. After that, you can place your circuit into a plastic casing that has a hole. You can make the hole by drilling into it just to enable the antenna to fit into it.

To build a sensitive voltage detector, you need:

  • 3 2N3904 transistors
  • 1M-ohm resistor
  • 100k-ohm resistor

Building a Sensitive Voltage Detector

Ideas on Building a Sensitive Voltage Detector

  • First thing that you need do is to insert a transistor right into your breadboard. This is to enable all of its three leads to be in separate columns.
    • You need to add the second and third transistors according the same method mentioned above.
    • You should place them in such a way for them to be able to alternate between the top and also the lower breadboard part, or they should be separated from the others by at least four to six columns.
  • The next step is to add your 1M resistor onto the breadboard.
    • Make use of a jumper wire so that you can connect one end to the first transistor’s collector lead.
    • After that, you have to use another wire so that you would be able to connect the other end of your resistor’s right to the source row of the voltage.

    You would be able to find the voltage source row normally near the top of your breadboard and it is indicated with a red sign.

  • After that, the 100k resistor should be connected to the second transistor’s collector lead.
    • In order to connect the resistor’s free end right to the voltage source, you can simply make use of a jumper wire to connect them.
  • One end of the 220 resistor should be wired to the third transistor’s collector lead.
    • The LED must be set near to the resistor.
    • In addition, you need to ensure that its leads are always in separate columns.
    • Then, you have to connect the negative lead of your LED onto the resistor’s free end.
    • Once finished, you can proceed by wiring the LED’s positive lead right to the source of your voltage.
  • The base of your first transistor needs to attach to the base of your second by connecting them together with a jumper wire.
    • Then, the second transistor’s emitter lead should be connected to the base of your third transistor according to the same manner mentioned above.
  • As for the third transistor’s emitter lead, you need to ground it by attaching a jumper wire between the transistor and the ground row.
    • You would be able to find the ground row near your voltage source one. It is normally indicated with blue colored stripe.
  • Then, you need to attach a jumper wire onto one side of the copper strip. The jumper wire should be at least 3-inches in length in order to connect the wire’s free end right to the base of your first transistor.
  • Once you have completed the above step, you can proceed by inserting a 9V battery or 4 AA batteries into its holder.
    • You need to attach the holder’s red colored wire onto the source of the voltage while its black colored wire attach to the ground.

    Always remember that whenever you want to build a sensitive voltage detector,

    • Make sure that you test the circuit thoroughly by bringing it close to your voltage sources. Be very careful because the circuit is very sensitive and it is capable of picking up static electricity. You can even bring it next to your hand as well as the monitor for your computer.

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