Hello,
I need to build a circuit to trip a 12V load on a signal from one of two sources.
One source is a +5V pulse that can trip a 5V relay on its own but the other source is the output from a IC rated at +3V 20mA (Max).
I have googled this for a week now and found that I need to use a NPN transistor to boost the IC output so it can trip the relay.
My problem is that I know next to nothing about transistors and the math behind them. And I have yet to find a tutorial I can grasp.
One way to build this is to have one input for the 5V source (connected directly to the relay) and another input for the 3V source (connected to the transistor).
Is it possible to build the circuit to have one input that can handle both sources? This to prevent users from plugging in the 5V source to the 3V input and possible fry the circuit.
Can some kind soul help me with a schematic and what components to use?
Thanks in advance.
Regards
Anders
I need to build a circuit to trip a 12V load on a signal from one of two sources.
One source is a +5V pulse that can trip a 5V relay on its own but the other source is the output from a IC rated at +3V 20mA (Max).
I have googled this for a week now and found that I need to use a NPN transistor to boost the IC output so it can trip the relay.
My problem is that I know next to nothing about transistors and the math behind them. And I have yet to find a tutorial I can grasp.
One way to build this is to have one input for the 5V source (connected directly to the relay) and another input for the 3V source (connected to the transistor).
Is it possible to build the circuit to have one input that can handle both sources? This to prevent users from plugging in the 5V source to the 3V input and possible fry the circuit.
Can some kind soul help me with a schematic and what components to use?
Thanks in advance.
Regards
Anders
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