TransWikia.com

Is my understanding of the roles of transistors in this circuit correct?

Engineering Asked by Tuna Yılmaz on November 27, 2020

enter image description here

THE CIRCUIT’S FUNCTIONING
This circuit is a rain water sensor circuit that buzzes when there’s water on a probe.I found it on net.1

CIRCUIT COMPONENTS

  • 3 Volts Battery
  • BC 558 Transistor(PNP)
  • BC 548 Transistor
  • 330K Resistor
  • A Water Prob
  • 10K Resistor
  • .01 Microfarads Capacitance
  • Any Speaker

MY UNDERTANDING OF TRANSISTORS ROLE

If NPN transistor(BC 548) in this circuit is working properly,emitter should have less current than collector,which is enough for speaker.Collector-side gets a high voltage which gets grounded by PNP transistor’s collector.(BC558)

If there’s a problem with Bc548 then emitter will have lots of voltage,thus collector will have less.Which means PNP transistor on there is used to shut down the circuit if there’s a problem.(If a PNP transistor gets low voltage from base,the current from emitter starts to flow to collector which means shutting down the circuit,causing all coming current to go to grounding for avoiding burning the speaker.)

Is my understanding of transistors roles correct?

Thanks for the help.

1-https://www.elprocus.com/simple-electronic-circuits-for-beginners/

Add your own answers!

Ask a Question

Get help from others!

© 2024 TransWikia.com. All rights reserved. Sites we Love: PCI Database, UKBizDB, Menu Kuliner, Sharing RPP