Archive for April, 2008
Quatz oscillator
This quartz oscillator circuit has greater stability than a parallel resonance circuit. It generates frequencies up to 30 MHz or even higher if you use BFR 91 T1, T2 transistors and reduce R1 … R2 values. The MOSFET buffer insulate the oscillator from any connected circuit.
Radio field signal strength indicator
A radio field signal strength indicator is very usefull for determine radiation patterns of transmitters antennas. An ancillary antenna must be put close to main transmitter antenna. The received signal is applied to L1,L2 and C2, this allows the field indicator circuit to adjust to the same frequecy as the transmitter. With the coils values [...]
Electronic Dog Caller Circuit Schematic
With this electronic dog caller circuit you can call your dog. Dogs can hear audio frequencies higher than humans do. This dog whistle schematic does not guarantee that only dogs can hear the sound, canaries, childs and even some adult peoples might hear the sound.
With 9V supply this power oscillator ( N1 … N3, R1 [...]
