Hello
I've download (using google) the TX-2B/RX-2B datasheets,
Iwill focus on the crystal oscillator built around Q1:
I have a toy car, the transmitter unit is working on 3 Volt. It's a replica for the circuit in the datasheets. Only difference in the values of the elements:
For the last figure, the 40MHz crystal is connected between two different voltages; the 3V at the collector and the approx. 1.2V at the base. This voltage difference is making crystal to oscillate.
Question1: Where this oscillating signal is fed, Is to base , collector or both?
Question2: What is the function of C1? Is it doing a feedback from collector to Emitter?
Question3: Is the above configuration a common emitter crystal oscillator?
Question4: I built the circuit and measure the operating point (IC = 22mA, VCE = 2.5V), is this a good Q-point? 22mA be withdrawn from a 3V battery is a very big current. It will be voided battery quickly.
Thank you for your patience to my many questions
I've download (using google) the TX-2B/RX-2B datasheets,
Iwill focus on the crystal oscillator built around Q1:
I have a toy car, the transmitter unit is working on 3 Volt. It's a replica for the circuit in the datasheets. Only difference in the values of the elements:
For the last figure, the 40MHz crystal is connected between two different voltages; the 3V at the collector and the approx. 1.2V at the base. This voltage difference is making crystal to oscillate.
Question1: Where this oscillating signal is fed, Is to base , collector or both?
Question2: What is the function of C1? Is it doing a feedback from collector to Emitter?
Question3: Is the above configuration a common emitter crystal oscillator?
Question4: I built the circuit and measure the operating point (IC = 22mA, VCE = 2.5V), is this a good Q-point? 22mA be withdrawn from a 3V battery is a very big current. It will be voided battery quickly.
Thank you for your patience to my many questions
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