| ??? 09/30/11 13:24 Read: times |
#183950 - RE:about filament Responding to: ???'s previous message |
Filament is warm wire with 2 ends ,inside VFD lamp.
It shold be somehow biased to anodes and grids. So You have Vb=-20V bias. Anodes and grids are connected by driver to VEE or to Vb . So we have Vee=5V DC for driver logic and Vb=-20V for filament bias. Vee-Vb=25V is Anode-Cathode voltage of VFD lamp. This is Your circuit. Not clear is - who powers filament. There are 3 possibilities: - AC voltage from transformer, - secondary negative Vb1 DC ouput, connected to second filament pin; - independent DC source , connected to 2 pins of filament. In last two cases You can regulate filament warmig trough PWM - assuming VFD is dynamically controlled display at some frequency about 50..80 Hz, PWM should be in 200..1000Hz range. Is this Your case? |
| Topic | Author | Date |
| How to control Grid voltage of VFD | 01/01/70 00:00 | |
| what You mean? | 01/01/70 00:00 | |
| bought as module or built by you? | 01/01/70 00:00 | |
| voltage is steady | 01/01/70 00:00 | |
| RE: "I purchase it from market" | 01/01/70 00:00 | |
| I have | 01/01/70 00:00 | |
| how | 01/01/70 00:00 | |
| code | 01/01/70 00:00 | |
| GO OUT FROM INTERRUPT | 01/01/70 00:00 | |
| filament power ? | 01/01/70 00:00 | |
| ISR changed, FILAMENT IS... | 01/01/70 00:00 | |
| Link about VFD | 01/01/70 00:00 | |
| what i should read there? | 01/01/70 00:00 | |
| Same problem with modified code | 01/01/70 00:00 | |
| Work on hardware | 01/01/70 00:00 | |
| show pictures | 01/01/70 00:00 | |
| DC connection | 01/01/70 00:00 | |
| Near to solution | 01/01/70 00:00 | |
| just a thought | 01/01/70 00:00 | |
| Thanks | 01/01/70 00:00 | |
| Modified program | 01/01/70 00:00 | |
| make report | 01/01/70 00:00 | |
| about Filament | 01/01/70 00:00 | |
| RE:about filament | 01/01/70 00:00 | |
PWM | 01/01/70 00:00 |