here is the printed circuit board version i biult today , first theres the keychain lazer power supply, and allso the receaver unit, in the picture of the receaver unit the 100k pot is outside the picture so youll know its there now ,that circuit has 2x 9 volts battery one is for the actual circuit and the other for the laser alignment led which goes off when the laser is lined up with the photo transister so when the beam is brocken the led comes on and allso any other warning circuit linked up to it
View attachment 38257
View attachment 38257
audioguru2
- Apr 6, 2004
- 12,026
- Joined
- Apr 6, 2004
- Messages
- 12,026
Hi Steven,
1) What is the voltage across the laser diode in operation?
2) What is its current? You can calculate its current by measuring the voltage across the 10 ohm resistor.
3) What is the dropout voltage of the 7805 regulator? Its output voltage will no longer be regulated when the battery voltage is about 7V.
Since a 9V battery's voltage drops to 6V during its life, I always use an LM2931AZ 5.0 low-dropout regulator in my 9V battery powered circuits. It continues regulating when its supply is only 5.4V and it is in a small transistor case. ;D
1) What is the voltage across the laser diode in operation?
2) What is its current? You can calculate its current by measuring the voltage across the 10 ohm resistor.
3) What is the dropout voltage of the 7805 regulator? Its output voltage will no longer be regulated when the battery voltage is about 7V.
Since a 9V battery's voltage drops to 6V during its life, I always use an LM2931AZ 5.0 low-dropout regulator in my 9V battery powered circuits. It continues regulating when its supply is only 5.4V and it is in a small transistor case. ;D
audio guru welcome back well at first i measured the voltage of the keychain laser button cells which i think i mentioned how much voltage it was before but because they are used batteries the figure may not be acurate so i used the 5 volts regulater powerd by the 9 volts battery that was allso used and so its actual voltage i thinkj i mentioned that to or not so then if the voltage drop through the regulater is sufficient enougth and with the voltage drop and the resister lowering it more then i geuss it did the job even though i thinkj i mentioned before what the final output is after the resister even though the battery voltage is not 9 volts as its a used battery so as for the current well havent been botherd with it yet but will get to it but the amount of testing ive done short range testing i have one good thing to say about it and that is that it is working great and holds up no worries have i missed anything