[Systems Engineering Teachers' Mailing List] Appliance cutawaydiagrams

[Alex Roujnikov]

Hi SE and Electronics teachers.
 
This year I bought "Home and Car Burglar Alarm Module " kits for year 9 . This is DS, Volume 2, project 15.
 
All modules have the same fault: they are easily activated by N/O or N/C contacts but do not "drop off " voltage from the output, pin 3 afterwards. Capacitor charges up to 2/3 of Vcc  but Schmitt trigger at the input 2 does not flip. I spent some time valuating and contact DS staf.
 
DS staff was not very supportive, they adviced me "to check the circuit diagram".
 
Are you familiar with this particular kit? Shall I try LM 555 instead of TT logic NE or ?? Please advice.
 
 
Thank you, 
Alex Roujnikov,
Penola Catholic College

This Email and any attachments may be confidential and, if you are not the intended recipient, you must not disclose or use the information in this mail. If received in error, please notify us immediately and delete the Email and all copies. The school does not guarantee that this Email is virus or error free. The attached files are provided and may only be used on the basis that the user assumes all responsibility for any loss, damage or consequence resulting directly or indirectly from the use of the attached files, whether caused by the negligence of the sender or not. The content and opinions in this Email are not necessarily those of the school.