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2.45GHz RF
Signal Detector
This passive RF indicator hobby circuit is made from a
few simple parts. A bent piece of wire forms a 2.5GHz antenna. A 100uA moving
coil meter is used to display the relative intensity of the RF signal. Two
microwave rated detector diodes form a simple voltage doubler circuit, which feeds a
DC voltage to the meter movement, proportional to the RF field strength. This
circuit can be used with some cell phones and many cordless telephones. It can
also detect RF leaking from a microwave oven.
Links to electronic circuits, electronic schematics, designs for engineers,
hobbyists, students & inventors:
2 Watt Switching Power Supply - In this small switching power
supply, a Schmitt trigger oscillator is used to drive a switching transistor
that supplies current to a small inductor. Energy is stored in the inductor
while the transistor is on, and released into the load circuit when the
transistor switches off. The output voltage is dependent on the load
resistance and is limited by a zener diode that stops the oscillator when
the voltage reaches about 14 volts. Higher or lower voltages can be obtained
by adjusting the voltage divider that feeds the zener diode. The efficiency
is about 80% using a high Q inductor.... [Bill Bowden's website]
2.45GHz RF Signal Detector - Many cordless telephones, computer
networks and cell phones use a RF transmitter centered on the 2.45GHz band.
Using a microwave diode detector and 100uA meter, this passive circuit will
display the strength this signal. The drawing shows how a bent piece
of wire can be used as the antenna. …. [Hobby Corner Circuit by Dave
Johnson]
4 MHz Amplitude Modulated RF Source - A while back I needed an amplitude
modulated signal source at 4 MHz. This circuit was literally thrown together
with parts laying on the bench. I built it dead bug style on a piece of copper clad
board. It should work with little or no modification, other thano get it to oscillate,
and at higher frequencies, you might have to reduce the capacitor values a little.
Just be....(schematic / circuit added 6/07)
40 Meter Popcorn Superhet Receiver - The schematic for a no-frills,
relatively low-cost CW superhet receiver with a 4.00 MHz Intermediate frequency. There
is no AGC or RF gain control, however…(added 12/2009)
