Ceramic Resonator Bfo Circuit

455 khz tunable bfo circuit reply to thread.

Ceramic resonator bfo circuit. The objectives of if alignment are to ensure that all tuned circuits in the if stages are tuned to the same frequency and that this frequency is the correct frequency usually 455khz. I want to make a 455khz tunable bfo without any transformers based on the model on this page. This i found easier that trying to set it up with the frequency meter. I will try to get some photographs off to hans in the next day or so but life has been hectic over this weekend.

Discussion in general electronics discussion started by richard9025 feb 5. A ceramic resonator will not allow you to move the frequency more than a little. The circuit is extremely stable. Turn the receiver off and then on at any time and temperature the bfo frequency is exactly the same.

I taped a short length of wire from the output across the back of the circuit board and then adjusted the slug to give me the correct note. I built this because at the time i didn t have a signal generator that would perform am modulation. All about circuits. The filter s center terminal normally grounded is connected to the current limiting resistor.

The last time i checked i didn t find it on the site but. Just curious for input at this point i m not an egineer so i can t directly contribute to our community with such a pico sized hack. Crystal oscillator vs resonator. In conclusion has anyone any photos of a mini sized bfo circuit built with a ceramic resonator.

The following circuit uses a 455 khz ceramic resonator which gives good frequency. Perhaps they ll inspire me to build one hhny2all. Hi thanks for the comment. More about making coils.

It s not perfect but definitely helps tune the if coils in the elenco am kit. Ceramic resonators ceralock lead type two terminal csbla series. The input and output of the ceramic filter are tied together. Inverters u1d e along with ceramic resonator x1 form a stable 0 5 455 khz oscillator.

Nand gate u2a is the modulator and provides a 100 square wave modulated signal. Oscillation is near 455 khz stable within a few hz. This circuit was used to stop all the bfo drift.