Electronics Forum

Electronics Circuits & Projects discussion forum. Get help with electronics.


Capacitor Not Fully Charging

Discuss about electronic circuits here. Request help for circuits that you couldn't find anywhere else, how a circuit works etc. Discuss anything related to electronic circuits.

Moderator: pebe

Capacitor Not Fully Charging

Postby ISeeLED » Sun Jul 24, 2011 3:49 pm

Hi

I'm coming back to electronics after a few years and have been going through the book "Make: Electronics". I have made the following circuit:

Image

The gray part at the top works fine, the LED blinks on and off periodically as the capacitor charges up and discharges.

The black part at the bottom does not though. The buzzer does not sound at all and no current exits the cathode of the PUT. I checked the voltage at the anode and it seems that the capacitor only charges up to 2.5V then stops, but the voltage at the gate is 2.75V, so I believe the anode voltage is not high enough to allow current through the PUT.

I checked the capacitor in a circuit by itself and it does fully charge, but not in the circuit with the PUT.

I also checked the circuit with the capacitor from the gray part of the circuit diagram (2.2uF as opposed to 0.0047uF) and the buzzer does sound.

Can anyone point out any mistakes I have made or tell me why the buzzer does not sound when the smaller capacitor is used?

Thanks

Edit: I found the answer on a different forum. I thought a loudspeaker and buzzer were the same thing, so I used a buzzer when I was supposed to use a loudspeaker for this circuit as it's an audio oscillator. The relevant thread is here: http://forum.allaboutcircuits.com/showthread.php?t=57446.
ISeeLED
 
Posts: 1
Joined: Sun Jul 24, 2011 3:40 pm

Return to Electronic Circuits Help



Who is online

Users browsing this forum: No registered users and 4 guests

Osram Optotronic Ballast 40W LED 0-10V Dimmable OT40W/PRG1400C/UNV/DIM-1
$14.99
Osram Optotronic Ballast 40W LED 0-10V Dimmable OT40W/PRG1400C/UNV/DIM-1 pictureLot of 3 ADVANCE CENTIUM ICN-2S40-N RAPID START BALLAST F40T12 F34T12 F30T12
$34.99
Lot of 3 ADVANCE CENTIUM ICN-2S40-N RAPID START BALLAST F40T12 F34T12 F30T12 picturePhillips Advance Mark 10 IEZ-2S24-D Dimming Ballast- never used
$45.0
Phillips Advance Mark 10 IEZ-2S24-D Dimming Ballast- never used pictureOsram LU250/SUPER5-KIT Lumalux Magnetic Metal Halide Ballast 1-Lamp 250W 60Hz
$14.99
Osram LU250/SUPER5-KIT Lumalux Magnetic Metal Halide Ballast 1-Lamp 250W 60Hz picture


cron