How does this two transistor circuit work?

Ask QuestionAsked todayActive todayViewed 41 times

This post has been deleted and is no longer viewable0

Can anyone explain how this circuit works?

If Q1 turns on then does Q2 turn off or on?

bjtshareedit  follow  flagedited 30 mins agoJRE40k88 gold badges7070 silver badges114114 bronze badgesasked 49 mins agoNakh0d43922 bronze badges

• 1What do you think it’s supposed to do? Is this you’re own design? – Transistor 46 mins ago
• 1thank you for answered me by a question! it is not my design, I just try to simulate it. in mu opinion when Q1 is on, Q2 should be on also. but someone told me Q2 should be off – Nakh0d4 39 mins ago
• 1that person is incorrect. maybe they thought Q2 was npn, when it is in fact pnp. – BeB00 23 mins ago
• 1@Nakh0d4, I would like to see it as a question to test (1) if a learning with basic understanding of NPN/PNP BJT can do it within how long. (2) if a guy coming to a job interview can do it or not, and for how long. Suggestion: my first feeling is that I can do it within 15 minutes, and write up an answer in another 15 minutes. I would suggest a “challenge” with the following rules: use your smart phone stop watch to time your answer, but do NOT disclose your answer yet. Perhaps we can set a deadline of three days, or .. Comments and counter suggestions welcome. – tlfong01 23 mins ago   
• 1@tlfong01 I dont understand what you are talking about. are you suggesting a circuit like this would be suitable for a job interview as an electronic engineer? I feel like any competent professional engineer (i.e. someone who does it for a job) should be able to do this in about 8 seconds. – BeB00 18 mins ago 
• The circuit doesn’t do anything useful; it just consumes current and appears not to interface to anything other than the air that surrounds it hence it really doesn’t do anything. So, when @transistor asked you what it’s supposed to do he asked a very pertinent question because, without some insider knowledge about why it was designed, all that can be said is that it consumes some current and gets a little warm. So, what’s the point of simulating it – none. Do you understand what you are doing or why you are doing a simulation because, without some proposed functionality, the circuit’s useless – Andy aka 13 mins ago
• @BeB00, Let me introduce myself. I completed an EE diploma ages ago. Then I went to job interviews for electronics technician jobs, mainly repairing rejected transistor radios (usually Philips, yes, those were the days). The candidates would be given 5 or 6 broken radios and try to troubleshoot, and report something like: (1) sample 1 has battery wire broken, poor contact etc. I still remember in some of the interviews, my hands were trembling when doing the testing, … – tlfong01 11 mins ago   
• My suggested “challenge” is for newbies, ninjas, and pros. It is sort of self assessment test for myself to make sure if I have lost some of my transistor knowledge and so called critical thinking in troubleshooting jobs. By the way, I only learn BJT and very little MOSFET in college. Now I am learning MOSFET. Perhaps later I can make up some MOSFET questions to test myself and other newbies, … – tlfong01 4 mins ago    Edit   
• @tlfong01, please don’t forget that comments are for seeking clarification on questions or answers. They are not for a personal blog or irrelevant chit-chat. – Transistor 3 mins ago
• Thank you for your advice, perhaps I can create a chat room in this or other forums to make this off topic comments. Thanks again. – tlfong01 1 min ago   Edit