In this article a positive DC voltage is converted into a negative DC voltage using a positive to negative voltage converter circuit, which is useful for a variety of electronic applications.
One popular and adaptable integrated circuit that is well known for its dependability and simplicity of usage is the IC 555 .
The IC 555 is frequently used in an astable mode to produce a square wave signal in the context of voltage conversion.
Circuit Working:
Parts List:
| Component | Value | Quantity |
|---|---|---|
| Resistors | ||
| 4.7k | 1 | |
| 33k | 1 | |
| (All resistors are 1/4 watt unless specified) | ||
| Capacitors | ||
| Ceramic | 0.022μF | 1 |
| Ceramic | 0.01μF | 1 |
| Electrolytic | 22μF 25V | 1 |
| Electrolytic | 100μF 25V | 1 |
| Semiconductors | ||
| IC 555 | 1 | |
| Diodes IN4001 | 2 |
In the above circuit diagram IC 555 is configured as an astable multivibrator that converts positive voltage +12V to negative voltage -12V and generates a continuous square wave output.
To produce the negative voltage, this square wave powers a switching mechanism that frequently consists of an resistors, capacitors and diodes.
To get a negative voltage from a positive voltage source is demonstrated by the above circuit design which is experimented on vero board.
This circuit also has the benefit of simulating a dual supply by using the negative voltage in conjunction with the original positive supply.
Always a few volts less than the positive supply, that is the negative voltage output.
Timer IC 555 is the foundation of the circuit, as an astable multivibrator running at around 1 KHz, the IC 555 is connected, a holder has to be installed on the IC 555
If accessible, pin number 3 of the IC will provide the square wave output.
Capacitor C3 charges through diode D2 during the positive half of the square wave.
Capacitor C4 is charged and C3 discharges through diode D2 when the output of the IC is zero.
C3 and C4 need to have a minimum 25V rating.
Loads that need greater current than 50 mA should not be connected.
This means that there will always be a negative voltage at the junction of the cathode of C4 and the anode of D1, relative to ground.
Formulas:
You must be able to choose component values and compute specific parameters in order to create a positive to negative voltage converter circuit using the above parts mentioned in the circuit diagram.
Here it provides the necessary formulas to built your own circuit..
Calculation of 555 Timer Frequency:
When the IC 555 is set up in astable mode, two resistors R1 and R2 as well as a capacitor C, define the output frequency f.
The general frequency formula is as follows:
f = 1.44 / ( R1+2 * R2) *C
where,
- R1 and R2are resistances in ohms.
- C is the capacitor in farads.
Capacitor Value C:
The capacitors filter the output voltage and reduce ripple.
The value of the output capacitor Cout is estimated by:
Cout = Iout * D * (1−D) / f * ΔVout
where,
- Iout is the output current.
- Vout is the allowable ripple voltage.
You may construct and adjust the positive to negative voltage converter circuit to fulfill your unique needs by using these formulas.
How to Build:
To build a Simple Positive Voltage to Negative Voltage Converter Circuit you need to follow the below mentioned steps:
- Gather all the required components mentioned in the above circuit diagram:
- Connect pin 1 of IC 555 to ground.
- Connect pin 2 of IC 555 to pin 6.
- Connect pin 3 of IC 555 to -12V output through capacitor C3 and diode D1.
- Connect pin 4 and pin 8 of IC 555 to +12V positive supply.
- Connect pin 5 of IC 555 to ground through capacitor C2.
- Connect a resistor R2 between pin 6 and pin 7 of IC 555 and a capacitor C1 to ground.
- Connect a resistor R1 from pin 7 of IC 555 to positive supply.
- Connect a diode D2 between capacitor C3 and diode D1 and ground.
- Connect capacitor C4 between diode D1 and -12V output to ground.
Conclusion:
A workable way to create a negative voltage from a positive supply is with a basic positive to negative voltage converter circuit.
It is essential to comprehend the circuit design, utilize components within their rated limits, and put protection measures like appropriate insulation and fusing in place to assure safe and efficient functioning.
Through meticulous testing and circuit prototyping, you can minimize risks and potential failures while achieving dependable performance.
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