|
Eëåêòðîíèêà Dosmen systems http://www.oocities.org/dosmen |
|
ÒÅÑÒÅÐ ÇÀ ÊÂÀÐÖÎÂÈ ÐÅÇÎÍÀÒÎÐÈ - 1 |
 |
|
ÒÅÕÍÈ×ÅÑÊÎ ÎÏÈÑÀÍÈÅ |
|
How it works: A crystal-controlled untuned oscillator composed of
Q1 and its associated components "turns on" Q2 if the crystal
oscillates; Q2 in turn lights the lamp. No oscillation, no light. Construction and Operation: Parts layout is not critical. If possible, first prototype the circuit on a breadboard to see if it works. To check the tester, use a crystal of a frequency you can monitor on your receiver, put the tester close to the the input of the receiver and close the switch. If you hear the signal and the lamp lights, the crystal, tester, and receiver all work. After that test, you can assume that if the lamp lights a crystal under test is good. The tester should operate well for any crystal with a fundamental frequency from about 2 to 8 MHz. Harmonics are also generated by the tester, although due to the lack of tuned circuits overtone crystals will oscillate at their fundamental frequency. |
