Schematics The Lie Detector Circuit

Here is the figure that shows to us about design circuit of the lie detector circuit;

In this circuit, it has the two probes shown are held in the hands and the skin resistance applies bias to the transistor. The 5 k ohm pot is set for zero deflection on the meter. When the "subject" is embarrassed or lies, sweating on the hands takes place, increasing the bias to the transistor and upsetting the bridge balance.[Circuit diagram source: Seekic.Com]

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Schematics Dual Detector Prevent Locking On Sidebands

Here’s the figure of the design circuit for dual detector to prevent locking on the sideband circuit.

Anti sideband circuit rejects side-band locking while telemetry tracking loop is automatically searching for signals around i-f value. Circuit also provides both p-m and aim demodulation. Emitter-follower Q1, receiving i-f signal, feeds discriminator Q6-07 through limiters Q2-Q3 and Q4-05. For 455-kc input, d-c outputs of diode detectors cancel at hose of Q8. For lower or higher frequencies, difference voltage serves to apply anti sideband error signal to loop fiber through Q9 or Q10. [Circuit diagram source: Seekic.com]

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Schematics Crystal FM Detector Circuit

This is a design circuit for crystal FM detector circuit. Here’s the figure of the circuit;

Exar XR-215 PLL IC is operated as crystal-controlled phase-locked loop by using crystal in place of conventional timing capacitor. Crystal should be operated in-fundamental mode Typical pull-in rangeis±1kHz at l0 MHz. [Circuit diagram source: Seekic.com]

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Schematics Bat Detector Circuit

This circuit is a simple design circuit for bat detector circuit that is a frequency division type device. Frequency division type detectors allow you to hear ultrasonic sound by digitally scaling the frequency down into the human hearing range. Here’s the figure of the circuit;

Basically this circuit is essentially composed of 3 integrated circuits, or ICs. The signal from an ultrasonic transducer is fed to IC-1, an LM386 audio amplifier, which is configured to provide a signal gain of 200. The signal is coupled to IC-2, a second LM386, by a .05 uf capacitor. IC-2 is configured to provide an additional gain of 20, for a total system gain of 4,000. The output of IC-2 is direct coupled to the input of IC-3, a 7 stage CMOS digital divider circuit. 

The input stage of the divider acts as a zero crossing detector, triggering on the negative transition of the signal from IC-2. The divide by 16 outputs connected to a potentiometer, which serves as an audio level control. A high impedance ceramic earphone is connected to the output of the level control. The 10K level control is a small printed circuit pot that is set and forgotten. The detector circuit is powered by a nine volt battery. (The numbers next to the IC nodes refer to the pin numbers of the IC's. Note the additional pins listed at the bottom of the schematic that need to be tied to ground).

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