06.01.2014Tranzistor jako relé
You are not going to find a relay that can be directly driven from the chip, it just isn't done that way in the industry. You need to use a pass transistor for powering the relay from the same power supply that powers the MSP430 . That is why I said 5V relay. It is a really simple circuit to build. Takes 4 parts.
relay - your choice as long as the coil current is below what the transistor can provide.
transistor - generic npn type, 2n3904 works fine
resistor - 10K ohm , 1/4 watt
diode - 1N4004 or similar
In this circuit the MSP430 sends a signal through the resistor. The resistor limits the current to the transistor and turns on the transistor causing it to conduct between the collector and emitter providing power to the relay. The transistor powers the load so the MSP430 load is negligible. When the relay turns off there is a pulse created in the coil of the relay across the pins connected to the transistor. The diode clamps that pulse so it doesn't harm the transistor.
Source: Hackaday
Transistor in GME: http://www.gme.cz/2n3904-p215-003, Datasheet
relay - your choice as long as the coil current is below what the transistor can provide.
transistor - generic npn type, 2n3904 works fine
resistor - 10K ohm , 1/4 watt
diode - 1N4004 or similar
In this circuit the MSP430 sends a signal through the resistor. The resistor limits the current to the transistor and turns on the transistor causing it to conduct between the collector and emitter providing power to the relay. The transistor powers the load so the MSP430 load is negligible. When the relay turns off there is a pulse created in the coil of the relay across the pins connected to the transistor. The diode clamps that pulse so it doesn't harm the transistor.
Source: Hackaday
Transistor in GME: http://www.gme.cz/2n3904-p215-003, Datasheet
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