Showing posts with label a. Show all posts
Showing posts with label a. Show all posts
Sunday, May 5, 2013
Make a Photodiode Alarm Diagram
This Photodiode based Alarm can be used to give a warning alarm when someone passes through a protected area. The circuit is kept standby through a laser beam or IR beam focused on to the Photodiode. When the beam path breaks, alarm will be triggered.
The circuit uses a PN Photodiode in the reverse bias mode to detect light intensity. In the presence of Laser / IR rays, the Photodiode conducts and provides base bias to T1. The NPN transistor T1 conducts and takes the reset pin 4 of IC1 to ground potential. IC1 is wired as an Astable oscillator using the components R3, VR1 and C3. The Astable operates only when its resent pin becomes high. When the Laser / IR beam breaks, current thorough the Photodiode ceases and T1 turns off. The collector voltage of T1 then goes high and enables IC1. The output pulses from IC1 drives the speaker and alarm tone will be generated.
The circuit uses a PN Photodiode in the reverse bias mode to detect light intensity. In the presence of Laser / IR rays, the Photodiode conducts and provides base bias to T1. The NPN transistor T1 conducts and takes the reset pin 4 of IC1 to ground potential. IC1 is wired as an Astable oscillator using the components R3, VR1 and C3. The Astable operates only when its resent pin becomes high. When the Laser / IR beam breaks, current thorough the Photodiode ceases and T1 turns off. The collector voltage of T1 then goes high and enables IC1. The output pulses from IC1 drives the speaker and alarm tone will be generated.
Photo-Diode Alarm Circuit
Monday, January 28, 2013
1994 Volvo 850 Turbo Change the ECU with A Non Turbo ECU Parts
When the ecu of my 1994 Volvo 850 Turbo was showing some bad readings about the knock sensors, I picked and pulled the old ecu and got a new ecu from a 1993 volvo 850 non turbo. Is it possible for an ECU from a turbo car to replace ecu from a non turbo car? Thanks.
Answer: No. The turbo creates a significant change, since the engine compression is changed significantly. VVT
A/F Ratio
Wastegate control
Banked injection
Would be different or missing from the ECU. The knock sensor sends signals when the A/F mixture pre-detonates before it can be ignited by the spark plug, and the computer corrects it with VVT. You need to buy the correct ECU.
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