Transistor switching Circuit

This circuit uses a transistor to switch on an output when the input voltage exceeds 0.6-0.7V. The two multimeters connected will show the voltage at the Input (the base of the transistor) and the voltage at the output (the emitter). When the input multimeter reads >0.7V the output multimeter should register a voltage that is >0V. This circuit would be useful if a low voltage input e.g an LDR was to be used to switch on an output that would need to be ran straight off the battery e.g a Bulb. The 1K ohm resistor is used to protect the transistor at the input.

Parts List

• Multimeter (optional)
• Transistor such as BFY51
• Breadboard or similar
• Input device- LDR or switch etc
• Output device- bulb or motor etc
• 1K ohm resistor
• Single core wire- for connections on breadboard

Navigation

Home
Back to simple circuits list