coll circuit

Tuesday, April 9, 2013

FM Moulator with IC 555

FM Modulator circuit is a simple FM modulation circuit using IC 555, where the resulting modulated signal has a tenuous meeting depends on the signal frequency information.

The resulting signal can be spelled out quite nice and stable so that the result will be more perfect. No winding or inductor in series modulator, so you do not need to bother to make a winding and calculate the value of the coil that you created it. With this circuit the desired value of frequency modulation can be obtained easily by calculating the frequency of IC 555 in general, which is determined by the resistor 6.8 K and 3.3 K and 0.1 UF capacitor. To obtain the other frequencies of your stay replace one or all three components.

Actually fm modulator ic 555 circuit is very simple though, but I think it reliable enough to handle a simple application purposes that do not require a big power or a very high frequency. But if you want more power you can add the RF amplifier circuit at the output of this circuit. Thus, the results of modulated signal can be amplified with the help of a series of supporters. In accordance with my experimental series modulators can work well at frequencies below the MHz range, because it is not IC IC 555 which is devoted to support of a very high frequency. You can use oscilltor transistor circuit, XTAL or others if you need a very high frequency.

The difference circuit with IC 555 on the multivibrator circuit in general is the use of pin 5, on the FM Modulator circuit is pin 5 of IC 555 is used as input information signal, which in turn will influence the shape of the output signal (modulated). But in applying this 5 pin multivibrator functions normally associated with 0.01 UF capacitor or left alone.

Saturday, April 6, 2013

555 timer chip tester

IC 555 timer tester is a simple circuit that serves to test the condition of IC 555. 555 timer circuit tester, in principle, start the timer 555 in astable multivibrator mode. As an indicator of the status of the timer 555 good condition or damaged to use 2 pieces LED which will light up in a blink alternately when the timer 555 in good condition.

And only one will turn on or off all the timer 555 when the condition is broken. 555 timer circuit tester is powered using 9 Volt DC voltage source. Complete circuit tester 555 as follows.

Tester schematic

How to use 555 timer tester is in conjuction with IC 555 to test the existing IC socket according to the orderbutton. Then activate the power switch to begin testing the 555 timer ic. Then live we observe the LED indicators 2buah before, whether flashing alternately (good) or not blink or even die all (timer 555 damaged).

Wednesday, March 20, 2013

Extend Timer Range For The 555

Anyone who has designed circuits using the 555 timer chip will, at some time have wished that it could be programmed for longer timing periods. Timing periods greater than a few minutes are difficult to achieve because component leakage currents in large timing capacitors become significant. There is however no reason to opt for a purely digital solution just yet. The circuit shown here uses a 555 timer in the design but nevertheless achieves a timing interval of up to an hour! The trick here is to feed the timing capacitor not with a constant voltage but with a pulsed dc voltage. The pulses are derived from the un smoothed low voltage output of the power supply bridge rectifier.

Extend Timer Range For The 555 cirucit diagram

The power supply output is not referenced to earth potential and the pulsing full wave rectified signal is fed to the base of T1 via resistor R1. A 100-Hz square wave signal is produced on the collector of T1 as the transistor switches. The positive half of this waveform charges up the timing capacitor C1 via D2 and P1. Diode D2 prevents the charge on C1 from discharging through T1 when the square wave signal goes low. Push-button S1 is used to start the timing period. This method of charging uses relatively low component values for P1 (2.2 MΩ) and C1 (100 to 200 µF) but achieves timing periods of up to an hour which is much longer than a standard 555 circuit configuration.

Circuit Source: DIY Electronics Projects