Various diagram: frequency

Thursday, November 6, 2014

RF detector circuit for High Frequency

Often we need to see which is ideal for the placement of an antenna, a transmitter or other device for high frequency where its signal can reach and where it leaves point. For this we can use a detector circuit, also called the sniffer, which is tuned to the operating frequency of the desired system. This detector is described in this article is very simple to operate and do, just uses two diodes and two transistors and a half dozen passive components, their frequency of detection is around 2.2Ghz and its sensitivity is pretty good.

RF detector circuit for High Frequency

Its operation is simple, the transistors Q1 and Q2 are BFS17 are being used with RF amplifiers. LED1 can be replaced by a VU to have greater precision in signal check. The circuit has a very broad frequency tuned, it will capture RF signals from microwaves, cell phones, WIFI, etc.. I believe that the transistor can be replaced by BFS17 BRF92 or BFG591, which are easier to find here.

Detector RF High Frequency

The circuit must be mounted in a metal box to minimize capacitive effects of hand and other external interference, only the antenna must be out of caixa.Para test the detector, as you approach a signal source, the 1 LED gets brighter. The simplicity of the circuit, for sure it will capture unwanted signals, especially harmonics powerful transmitters, but is still reliable equipment.

Sunday, October 26, 2014

A Frequency Doubler Effect for Electric Guitar

This circuit is a octave shifting that is used for electric guitar is done by rectifying the original signal, just like AC to DC conversion inside your AC-DC power supply adapter. This circuit is use single supply instead of symmetric power supply. This is the figure of the circuit.
The rectifying is done by four 1N4148 silicon diodes, configured as full-wave rectifier bridges. Because the bridge is inserted inside the negative feedback of the operational amplifier (op-amp) U1B, the nonlinear characteristic of the diodes around the turn-on point (the forward bias voltage) is compensated by the op-amp’s feedback mechanism.

Thursday, October 2, 2014

Voltage and Frequency Calibrator Circuit Using IC 555

This circuit of a voltage and frequency calibrator provides simultaneous voltage and frequency calibrations by generation of a precision squarewave.
The 555 timer IC is used in a slightly unusual configuration, having the advantage that an exact 50:50 mark/space ratio may be attained by trimming R1. The frequency of oscillation may be set between l0 kHz and 1 kHz by switching timing capacitors C14. C5 decouples the internal ref- erence potential-divider of the 555 from supply·transients. The squarewave output from pin 3 of the IC, while stable in frequency, is not stable in peak-to-peak voltage as this depends on the supply voltage. This is used to switch on and off a temperature compensated constant- current source O1. R2 ensures that the current·source turns off completely when pin 3 goes high. The current- source output, trimmed by R3 to be exactly 1 mA, drives a resistor ladder network so that a series of precise squarewave voltages are generated. The advantage of current drive rather than voltage drive for this sort of net- work is that calibration is much easier. A simple ladder network is shown by way of example, and more complex ones may simply be constructed to give a wider variety of output voltages. The non-standard component values used were obtained by paralleling standard values. For the timing capacitors several in parallel had to be used, and only the resultant value is shown on the diagram.

Monday, September 1, 2014

Mains Frequency Monitor

Mains Frequency Monitor Circuit Diagram. Here is a simple frequency counter designed to monitor the 240VAC mains supply. It as a frequency range of 0-999Hz, so it could also be used with 400Hz equipment. Standard TTL/CMOS logic is employed for the counters and display drivers, while an ELM446 (IC1) generates accurate 1Hz pulses for gating. This device utilizes a 3.579545MHz crystal for its timebase, as commonly found in TV and video diagram and even on old PC motherboards.

Mains Frequency Monitor Circuit Diagram:

mains-frequency-monitor-schema

Mains Frequency Monitor Circuit Diagram

Thursday, August 14, 2014

Frequency Comparator II Wiring diagram Schematic

This is a Simple Frequency Comparator II Circuit Diagram. The schema provides unambiguous LED + or - bar readout with steps of 0.1%. The reference frequency is multiplied by the PLLIC1 and divider IC9 to output 64 ? F (ref) and this is then gated by dividing F (measure) by 32 in IC8 thus is F (ref) = (measure) then IC2 counts 1024 pulses.

Simple Frequency Comparator II Circuit Diagram

Should the count be more than 1031 than the latch IC4c/IC4a is set to indicate count too high (F (measure) F (ref)) and if the count is less than 1017 then IC3/IC4b indicate count too low (F (measure) F (ref). These signals are latched by IC5 at the end of each period by the latch signal from IC6e. When the two frequencies are within + or - 0.6% the LSBs of the counter IC2 are decoded and latched by IC7 and displayed on LEDs IC6c resets the counter after latching the data.

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