Help me..problem to triggered relay

[89Panadol]

Hai everyone...I have problem with my Ultrasonic Radar project..

•The problem is: 1)Motion detector cannot triggered relay.
2)When output from ultrasonic radar not connected to relay,the output voltage is almost 9v when it detect motion.
3)When output from ultrasonic radar connected to relay,the output voltage is just 2 v when it detect motion(not enough to triggered relay)

•This circuit use a pair of transistor BC547 as output to triggered relay.

•How i can increased the voltage when ultrasonic radar connected to relay..

•Link to project
http://www.high-voltage-lab.com/247/ultrasonic-radar

 

[IanP]

You don't need to "increase" voltage, the output pin [9] is O[pen]-C[ollector] - so it sinks current to 0V[gnd], and the relay has to be connected between pin[9] and Vcc, as shown on the attached picture ..

IanP
:|

 

[siongboon]

Hi,

I think you may be using a relay too big of a coil.
BC547 can only power up a coil up to 100mA.
Check your relay power consumption.
Power up your relay with power supply 12V.
Measure the current....

If it is > 100mA, you will need to interface the output
to another stronger transistor to drive a load
greater than what your relay need.

Best Regards,
Siong Boon

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[89Panadol]

Thanks everyone...I gonna try it..