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Can a transistor be used as a relay switch?
Transistor as a Switch for Relay Transistors are capable of driving small relays without any problems. Usually, an NPN transistor in a common emitter configuration used as a switch drives the relay. Here is a simple circuit that uses a bipolar junction transistor (BJT) to drive a small 5 V relay coil.
How is current calculated in a relay circuit?
Example: Relay 12 volts requires current flow through relay coil 100 mA, by use transistor that has gained 50 times, thus will calculate the input current as follows. Therefore the input current-Iin paid to second transistors equals 2 mA is current, that makes first transistor saturation occurs at voltage 12 volts.
How is a transistor used in a control circuit?
The controls circuit is the digital circuit, by use output pulse from micro controller or digital gate ICs. To control relay to works. But it is low current, so use a transistor to switch high current to drive the coil instead.
What does a relay driver do in a digital circuit?
All the relay driver circuits above are the pulse output of the digital circuit to control a transistor works and drive relay as an ON-OFF switch for circuit or external devices next, to using it now selected to suit the circuit.
Which is more reliable a relay or a transistor?
A relay may have many contacts, such as double changeover poles to implement complex logic. A disadvantage of a relay is that it is an electromechanical device and therefore less reliable than a transistor. The contacts may burn out, and the mechanical parts such as the armature may fail over time.
What should base resistor be for Raspberry Pi switch?
If your switching signal is 3.3 V from a Raspberry Pi, or Arduino, then the base resistance should be around 1 kΩ to 1.2 kΩ. Please use the Transistor Base Resistor Calculator if the input signal is 5 V or any other voltage.