Converter 9 to -5V Circuit

The below circuit is the circuit for the DC / DC converter. The converter has become converts the output voltage of 9V to -5V. This circuit is useful if your regular 9V / battery, but you have to -5V power supply for your electronics.
This circuit used popular IC 555 and sime circuit to build.

Police siren circuit

Come back to Free circuit today ,I would like to present the sound circuit that like police siren sound for your apply to another project ,

The Police siren circuit given here is based on a circuit NE 555 timer IC.
The circuit uses 2 each for NE 555 ICs (IC1 and IC2) and the core working parts of the circuit.
There are 2 timer ICs are wired to work as astable multivibrators. But these 2 timer ICs operate at different frequencies.
Regrading IC1 is slow unstable multivibrator operating at a frequency of 20 Hz and a duty ratio of 50%, while IC2 works as fast as 600Hz astable multivibrator.
The output of IC1 is fed to the control pin (pin5) of IC2. With this regard, the output of IC2 frequency modulated with the frequency output of IC1.

 The circuit can be powered by a DC voltage ranging from 6V to 15V. Power is used, the 12V DC. The volume of production can be increased by inserting an amplifier circuit on the output stage of this circuit.

Pulse Timer Control Relay Circuit

Today we would like to offers solutions for a set time for take control relay and take NO. / NC. contact to apply to control other devices . such as disable or enable the device.

function of this circuit is using IC555 to determine the pulse and a resistor R1 to the period of time.

R1           #Seconds
100k         2
220k         3
470k         6
1M           15

The increase provides more time to increase the value of the Capacitor.

Electronic Part List
R1 = 1 Meg, Preset Pot
R2 = 10K   
R3,R4 = 1K
C1 = 10uF, 16V
C2 = 0.01uF
T1 = BC547 (Gen Purp NPN)
T2 = 2N2222 (Hi Current NPN)
D1 = 1N4001 (Gen Purp Si)
IC1 = 555 (Lo-Power version)
RLA1 = Relay, 9V (amps of your choice)

DC to AC with IC555 circuit

AC to DC IC Series DC-AC inverter produces an output voltage alternating voltage network.

IC 555 configured for Low Frequency Oscillator. Frequency can be changed 1950-1960 change frequency meter Hz potens R4.

This DC-AC inverter schematic produces output AC power, and frequency. 555 is set to a low frequency oscillator, tunable in the frequency range 50-60 Hz, R4 potentiometer.

555 feeds output (which Q1 and Q2) to the transformer T1, a reverse filament transformer with the necessary step to turns ratio. Capacitor C4 and coil L1 filter the input T1, assuring that it is virtually a sine wave. Adjust the voltage of T1.
Output (in watts) you must select the different parts.

input voltage is anywhere +5 V +15 V DC, operating voltage CAP 2700uF adjust accordingly.
Q1 are the types of compensation: TIP41B, TIP41C, NTE196, ECG196, etc. Q2 types of parts are: TIP42B, TIP42C, NTE197, ECG197, etc. Do not be afraid to use another type of similar characteristics, only one transistor. ..

Parts List:

R1 = 10K
R2 = 100K
R3 = 100 ohms
R4 = 50K potmeter, Linear
C1, C2 = 0.1uF
C3 = 0.01uF
C4 = 2700uF
Q1 = TIP41A, NPN, or its equivalent
Q2 = TIP42A, PNP or equivalent
L1 = 1UH
T1 = filament transformer selection

If everything works well. If not, relax and do not get frustrated. Check the following:

1. You have connected the filament transformer so contrary?
2. Otherwise, unplug the power cord and vice versa. If you have, disconnect the transformer and measure the voltage after the L1 and the earth.
3. Only if the bottom of this neighborhood is the same as the negative (-).
4. Q1/Q2 are oposites, e.i. NPN / PNP.
5. Is it 555 defective? Remove the pin from 3:03 R3 to control impulses.
6. Check the transistor to make sure they are intact.

Error: Pin 7 and 2 were reversed. The original pin was correct.

The time sequence is generated using the CMOS 4017 decade counter and timer 555th Counter outputs 1 to 4 ares wire ORed with 4 LEDs, so the Red (- north / south) and (Green – East / West) LEDs will for the first four counts.

The fifth count (pin 10) illuminates (Yellow – East / West) and (Red – North / South).

Counts from 6 to 9 ares also wire or diodes control (Red – East / West) and (Green – North / South). Count 10 (pin 11) controls (Red – East / West) and (Yellow – North / South).

Deadline for red and green lights will be 4 times longer than the yellow and time to complete the cycle can be adjusted with the 47K resistor. 1N914 diodes eight could be subsituted with a dual 4 input or gate (CD4072).

LED traffic control circuit

Electrinic Part List

LM555              IC                  1pc.
CD4017             IC                 1pc.
2N3904             Transistor         4 pc
10K Ohms         Resistor          1pc.
47K Ohms          Resistor          1pc.
180 Ohms          Resistor          2pc.
Red                      LED               1pc.
Yellow              LED               1pc.
Green               LED               1pc.
1N914               Diode             8pc.
10uF/16V          Capacitor        1pc.
9V battery clips  Connector      1pc. (option)
PCB                                      1pc.

RLX resistor determines the brightness of the LED and current limiting for about 10 to 15mA when running between 9V to 12 VDC.
TRAFFIC flash scrolling speed is determined by the capacitors C1 and resistance R1 – C1 increases and reductions in R1, the slow speed.
For example, if the LM555 is set to generate one pulse per second, 1 Hz, the green light for 4 seconds to 1 yellow, red for 5

Xenon Strobe CIRCUIT 1

The circuit used to come in kit form with a surplus supplier, but it is probably more available. It shows some new concepts such as using a 555 as a pulse width modulator (PWM), and serial / parallel processors flash camera.
The 555 is mounted as a pulse width modulator (from the (low) time to be determined by the regulator). The output on pin 3 is connected to the gate of P-channel MOSFET (IRF9Z20) through the 100R resistor to prevent parasitic oscillation of the transistor. A low signal on pin 3 causes the MOSFET to turn, so the button controls the flash output and a bit rate, by varying the duty cycle of 555 and in turn the MOSFET.

Xenon Strobe CIRCUIT 2

Time Delay Relay with IC555 circuit

Parts List

C1    10uf 16V Electrolytic Capacitor
C2         0.01uf Ceramic Disc Capacitor
R1           1  Meg Pot
R2       10 K 1/4 Watt Resistor
D1,D2        1N914 Diodes
U1         555 Timer IC
RELAY          9V Relay
S1          Normally Open Push Button Switch

Remark:
1. We used R1 adjusts the on time.

2. You can get a different capacitor for C1 to change the maximum on time.

3. S1 is used to activate the timing cycle. S1 can be replaced by a NPN transistor so that the circuit may be triggered by a computer, other circuit, etc.

9 Sec. Timer control Relay circuit

IC 555 timer output at pin 3 will be high and the voltage at pins 6 and 2 of the timer will be a little less than the lower trigger point, or about 3 Vdc. 

That time the switch is opened, the transistor in parallel with the timing capacitor (22uF) is shut off allowing the capacitor to begin charging and the IC 555 timer circuit to produce an approximate one second clock signal to the decade counter. The counter advances on each positive going change at pin 14 and is enabled with pin 13 terminated low. When the 9th count is reached, pin 11 and 13 will be high, stopping the counter and energizing the relay. Longer delay times can be obtained with most capacitor or most resistor at pins 2 and 6 of the IC 555 timer