Schematics & BOM: LINK
STRIPBOARD LAYOUT
The stripboard layout has been updated on November 5th, 2022.
-All decoupling capacitor, 100nF, are soldered across Vcc and Vee of each ICs underneath the boards.
-For better V/Oct tracking, you can use a matched pair of 2n3906 and +3500ppm, 2k tempco resistor and place the tempco resistor between 2n3906s with thermal compound.
-In my case, the triangle output is around 8Vpp. So I replaced 2k which is connected 14pin of U3 with 1k to get 10Vpp.
FACEPLATE LAYOUT
MEASUREMENT
Sinewave
-It's the most rounded shape I can get. There might be some mistakes while building.
Triangle
Sawtooth
Pulse
Hello, I would like to build the Thomas Henry 555 VCO, and I found some resistors on your stripboard layout marked with red. 2K, 22K and 137K. Could you tell me why they are marked? Thank you in advance and keep up the good work! ;)
ReplyDeleteHi! First of all, sorry for my lack of explanation on this post. I'll update all the posts with more explanation sooner or later.
DeleteAnyway those red-marked resistors are ones from original schematic which was designed for 15v power supply. If you use 12v psu, you need to replace 2k with 3k, 22k with 39k and 137k with 100k.
Hope you build 555 vco without any problem!
Should be 2x 14 Pin IC socket and 1 each of 8 and 16 pin sockets.
ReplyDeleteI made it according to your circuit(I made it as shown in the updated circuit image). No matter how hard I check, there seems to be nothing wrong. However, the lm13700n chip gets very hot right after when I connect the power source, and there is no sound. What part should I check? please let me know. thank you in advance.
ReplyDelete