# Is there an easy way yo measure frequencies?

Discussion in 'General Electronics' started by beast, Feb 8, 2005.

1. ### beastGuest

Tesla didn't have an oscilloscope, so how did he figure out
frequencies?

I'm trying to make a tank circuit, but I don't have an oscilloscope.

2. ### MarkoGuest

Depending on the expected frequency, you could connect your oscillator
to an audio amplifier and listen. If you're expecting a frequency in
the range of the AM or FM band, you might be able to tune it in and
hear it when it starts up.

Back in the old days, people used a Vacumn Tube Volt Meter (VTVM)
connected to the grid of the oscillator tube. When the grid voltage
went negative (with respect to the cathode), it meant that the circuit
was oscillating. There was also something called a Grid Dip Meter
that was used for just this purpose.

Marko

On 8 Feb 2005 12:54:09 -0600,

3. ### Jim DouglasGuest

My meter will measure freq from 2kHz--> 15Mhz, not very high, but maybe
there are others that go into the range you are looking for, actually my
scope only goes to 25MHZ!'

4. ### ctyguyGuest

Best and cheapest is to work with the bacic formulas using Resonancefrom ,
Resistance, inductance/inductive reactance, capacitance/capacitive
reactance.

I'm afraid to list any, since I have not used them for years, but they're
accurate (or at least as accurate as pi <g>) As in 2(pi)fl

5. ### beastGuest

How about if I use a cheap am/fm radio to tune a circuit to one
frequency, and use another cheap am/fm radio that I tune to the same
frequency, and feed the tuned signal into the antenna circuit of the
other, that would give me a cascade wouldn't it? I'm just worried
that the amplifier circuit of the other will act to dampen the
output, so I'm thinking of just using the tuning loop by itself, and
have it excited by the output of the first LCR tuning loop.

Antenna, then LCR1 output to the antenna2. I think that should work.

7. ### beastGuest

Well, thanks for the help. The two radios only provide me with already
made tank circuits. I can always separate the coil/cap from the rest
of the cicuit, and use the parts can't I?

9. ### beastGuest

Robert Baerwrote:

.....?