Quote:
Originally Posted by FrancoItaly
Thanks for the compliments, there can be real progress only with the collaboration of everyone. The "phenomenon" that allows the operation of the lrls is still largely unknown, but it is as real as many members have already been able to verify. As far as possible I help everyone in the realization of my lrl and take this opportunity to summarize the useful advice for the construction:
- the sensor stage has a very high gain and therefore there is the risk of self oscillations, it is advisable to use a double-sided pcb with the lower face connected to the negative and on the upper one the components will be soldered, no holes are necessary , only that, if necessary, to connect the upper mass to the screen constituted by the lower face of the pcb.
- the transistors are of the BC183C type or equivalent (for example BC549C or others), also the BC183B can be used as long as the beta (gain) is higher than 500.
- the total value of C2 / C3 / C4 establishes how much the quartz oscillator signal will be amplified by the sensor stage and therefore
determines the output value.
- C13 / C14 determine the gain of the sensor stage, in fact, increasing the value of C13 / C14 lowers the actual value of R10 / R12 (for the frequency of 8Mhz) and therefore increases the gain of the stage.
- On the TR2 base there is the mixing between the 8Mhz signal and the "phenomenon" captured by the stylus antenna.
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Hi mr franco and thank you for your help
I tested bc548, bc547 b , bc 238b , bc 547c , and the results was same, my pcb is self oscillation, i have to use 20 pf capacitors for c13 , c14 to avoid from self oscilation
I think when i increase total value of c2 , c3 , c4 for increasing output voltage the lrl sensivity decreases
Now i have 2 question mr franco
1- how much is maximum amount that can be used for r10 and r12
2- does your lrl dont work with low voltage in output? ( for example 0.5 volts or 0.6 volts)