I'm just a beginner and need some assistance. below is a diagram of a 4CH reciever which works fine with some leds and it reports 5V positive on Data0 when holding channel 0 on the transmitter. What's not working is when attempting to use a 5V DC relay as shown in diagram, the relay clicks and seems to work fine with a direct input.
I'm using USB Powered socket which is 5V DC 0.5A I believe. I'm really puzzled while its not working.
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simulate this circuit – Schematic created using CircuitLab
Best Answer
The relay draws more current than that module can supply. If you keep doing such tests you may damage the receiver!
If you read the SC2272-M4 datasheet, you'll see it can supply a maximum current of 3 mA. That relay needs 89 mA at a 55 ohms coil resistance. So the load current is 5 / 55 = 0.09 A = 90 mA. Now, the minimum hFE of the transistor should be (0.09 / 0.003) x 5 = 150. The resistor between receiver and transistor base should be 0.2 x 55 x 150 = 1650 ohms. Choose 1.8 k. Calculations made on http://pcbheaven.com/wikipages/Transistor_Circuits/
Due to the very low available current from receiver output pin, a high hFE transistor is required. 2N2222 should work (its maximum hFE is 300).
Use a (transistor) driver. Something like: