This is the circuit diagram of audio/video modulator. The circuit will convert an audio and video signal into a UHF TV signal. It’s desired to connect a video signal originating from a camera or other video source to a normal TV set. The audio and video signal is converted into a UHF TV signal so that the signal can be received through the TV antenna input.
Audio/Video to UHF TV Signal – Parts List
| R1 : 47 R2 : 100 R3 : 560 R4 : 1K R5 : 1K R6 : 1K R7 : 10K R8 : 1K5 R9 : 1K5 R10 : 1K5 R11 : 2K7 R12 : 2K7 R13 : 2K7 R14 : 5K6 R15 : 270K RV1 : 50K (47K) RV2 : 1K ZD1 : 11V ZD2 : 6V2 |
C1 : 3pF C2 : 3pF C3 : 3pF C4 : 1pF C5 : 3pF C6 : 10pF C7 : 15pF C8 : 22pF C9 : 33pF C10 : 56pF C11 : 100pF C12 : 100pF C13 : 180pF C14 : 470pF C15 : 1nF C16 : 1nF C17 : 1nF C18 : 1nF C19 : 1nF |
C20 : 4?7 C21 : 4?7 C22 : 10?F C23 : 10?F C24 : 220?F CV1 : 5pF T1 : BC547B T2 : MPSH10 T3 : MPSH10 T4 : BFR90 L4 : 10,7MHz L5 : 10?H LD1 : Red |
High Frequency Inductor Windings
This is how to make high frequency inductors for L1, L2 and L3:
- Cut 3 lengths of the 0.6mm wire supplied to the exact length.
- Scrape the enamel off the ends of each length of wire with a sharp knife for about 5 mm and tin the ends.
- Make up the windings on a gimlet of 3.5mm diameter.
Download the application note of Audio/Video to UHF TV signal converter:
Hi,
I have two questions
1- what about the voltage?
2- there is “L5 : 10μH” in the parts list but i can’t find it in the schematic!
Thank you