Circuit Wiring

This is a circuit of Power-Fail and Low-Line Signals. This circuit is used to warn the processor when the power failure or a brownout is occurs. The processor will enter a power-down routine, when either of those signals interrupts the processor. Back up important data prior to the POR placing the processor in reset and cease its current  activities are things that the processor do when enter the routine. Here is the circuit.Power-fail comparator is used to create a power-fail signal by monitoring the unregulated DC voltage. The regulator powers both supervisor circuit and the processor by using the the unregulated DC voltage.

Power-Failure and Low-Line Signals Schematic


 The regulator’s output capacitor retains its output voltage, so the unregulated voltage drops before the regulator’s voltage. And also, we can know drop in the regulator’s voltage. The processor can enter its power-down routine prior to being reset, if the power supply voltage were to drop low enough because of Detecting the regulator’s voltage drop.A supervisor provides a low-line signal, which goes active whenever the monitored power supply drops to a level slightly above the reset threshold so the processor can still receive warning of an imminent power failure when there is no access to the unregulated voltage.

To cause the POR to issue a reset, the processor warned that the power-supply voltage may decrease enough by the low-line signal. To anticipate the POR generating a reset, the processor backs up important data because of power failure  or a brownout.

Component List :

R1 = 2,7R

R2 = 2,7R

C1 = 1uF

C2 = 1uF

C3 = 100uF

C4 = 220uF

C5 = 100uF

C6 = 100uF

C7 = 220uF

C8 = 0.1uF
C9 = 0.1uF

C10 = 470uF

C11 = 470uF

U1 = ULN3750B

The series of loudspeaker drivers are electronic circuits that function to bridge between high-output circuit with a loudspeaker berimpedasi berimpedansi low. 

Why this driver is needed so that the output voltage to be inserted into the loudspeaker is not impaired. Declining value of this voltage is very possible given the lack of rules regarding the distribution of voltage and resistance instead of parallel. Where every prisoner that is placed parallel with other prisoners or the inmates totally substitute for detainee custody is smaller than with individual prisoners themselves. For example, 10 ohm resistance 10 ohms paralleled with the prisoners would get custody instead of 5 ohms. Resistivity 10 ohm to 100,000 ohm paralleled the total resistance is 9.9990 ohms. So it can be concluded that the total voltage will always be smaller than the origin of each detainee. Then, with a decrease in resistance (only using a combination of resistors) or the impedance of the output terminals before, then in accordance with the laws of the voltage divider in series can be ascertained that the prisoners connect in series with output terminal will have a larger part of the voltage and output terminal itself will decline voltage.

The working principle speaker driver circuit is actually very simple and easy to understand. Where the input signal is only used as a trigger to move the second driver transistor to the rhythm of the input signal. While the current that would flow to the loudspeaker most of the power supply driver circuit. You could say similar to the use of transistors as switches. Therefore, in this speaker series driver not found a combination of resistors for reinforcement. So if we look at the picture above, so most of the current flowing in the loudspeaker load is derived from the 9 volt supply voltage, instead of the input ac signal, so that the input signal will not be burdened.

The series that we will make this is a special electronic circuit can be used to detect the presence or absence of signal AF / RF. The circuit is very neat and simple to make. Costs it takes quite cheap. If you are already assembling this circuit, then with easy reader determine whether there is AF or RF signal at a particular section of a circuit.

Basic circuit uses an audio amplifier and a loudspeaker with switch input for AF and RF signals. The whole device can be made small as possible so it can be included in a container to maintain security. Audio amplifier section in this series created by IC TDA 2822M, with low stereo power amplifier in 8-pin mini-DIP. IC is used as a bridge cofiguration to shrink to 250 mW output power, loudspeaker handle 4 ohm, 500mW. The current required is less than 10mA with voltage of 3V battery.

When the selector switch in the AF position, working on the input audio signal AF amplifier input (pin 7 of IC 1) through a capacitor C2 and potentiometer VR1. Capacitors C2 always hold input amplifier of the DC voltage and make it happen in the audio signal frequency. Input Signal IC 1 can be arranged with the help of potentiometers VR1.

When the selector switch in position RF and demodulator detector circuit formed by capacitor C1, diode D1, and resistors R1 and R2 are connected to the input The set. When the audio signal is detected then it will actually go kerangkaian to be strengthened. Signal detection is done by plugging probe (probe) on the legs of the existing components.

Changing the voltage to frequency scale in the design of an electronic device is sometimes necessary. The series of articles voltage to frequency converter with the XR 4151 is one answer. Voltage to Frequency converter circuit with the XR 4151 is the idea of time in college, when there are projects to create a tool to hatch chicken eggs.



It will be my neighbor also write articles incubators chicken egg-based microcontroller AT89C2051. Maybe there are friends who still remember to this project. Back to the topic of voltage to frequency converter circuit with the XR 4151. IC XR 4151 is a major component of voltage to frequency converter (Voltage to Frequency Converter).

From voltage to frequency converter circuit with XR 4151 on the input signal circuit is a DC voltage level. IC XR4151 on voltage to frequency converter circuit serves to convert the voltage level coming into form in the development of the frequency change, where the output frequency range of voltage to frequency converter with the XR 4151 is proportional to the voltage level input voltage to frequency converter circuit with this 4151 XR.