Archive for May, 2008
Crystal quartz oscillator
Another great quartz crystal oscillator schematic with bb139, a 2-nd harmonic quartz crystal and one BF214 transistor. So, the Q quartz is half of the desired transmitter frequency, L1 has 24 turns, 0.08mm Ø built on a 455kHz carcase. L2 has 8-9 turns / 0.8mm Ø / 5mm Ø. This quartz oscillator circuit has a [...]
Quartz crystal oscillator
A very simple crystal quartz oscillator circuit schematic which use a quartz for frequency stability and a good rf tranzistor. Use a 2-nd or 3-rd harmonic crystal , for example if you want 100MHz use a 50MHz or 33.3MHz quartz or if you want use a 4-th harmonic crystal but the output rf voltage [...]
Stereo encoder
This simple stereo encoder circuit schematic is build with 2 IC MMC4066E and MMC4047 and one transistor BC547B. On IC1 2 and 3 pins is the audio output which is amplified by T1 ( current amplification ). On IC2 pin 10 you can find 19kHz pilot tone frequency. To adjust the frequency rotate R13 [...]
