Transistor Based Battery Heater Circuit uses 12V DC with good heat and very portable.
Circuit is good for outdoor, no-electric place, small incubator and emergency heat.
It uses astable multivibrator with transistors.
Transistors switch power transistor and run heat coils.
LED show if circuit is working.
Circuit Working:
Parts List:
| Component | Value | Quantity |
|---|---|---|
| Resistors (All resistors are 1/4 watt unless specified) | ||
| 1.5M | 1 | |
| 3.3k | 1 | |
| 100k | 1 | |
| 1k | 2 | |
| Potentiometer 4.7M | 1 | |
| Capacitors | ||
| Ceramic 0.39µF | 1 | |
| Ceramic 0.47µF | 1 | |
| Semiconductors | ||
| Power Transistor TIP122 | 1 | |
| NPN Transistors BC547 | 2 | |
| LED any colour 5mm 20mA | 1 | |
| ON/OFF Switch SPST | 2 | |
| Heating Coil Wire wound 10W | 3 |
Q1 and Q2 make astable multivibrator and gives square wave signal non-stop.
In this circuit signal speed changes by R1, VR1, C1 and C2.
Q1 and Q2 switch fast and make pulse.
Pulse go to TIP122 Q3 base.
TIP122 Q3 act like switch and control power to heating coils.
When Q3 is ON then current go to L1, L2, L3 and make heat.
S1 and S2 pick which coil.
LED1 stop back voltage from coil.
Right coil means good heat.
Formulas:
Frequency of Multivibrator:
Formula:
f = 1.44 / ((R1 + 2VR1) * C1)
Values:
- R1 is 1.5M
- VR1 is 4.7M
- C1 is 0.4µF
How to Build:
To build a Transistor Based Battery Heater Circuit following steps need to be followed for designing our own circuit:
- Connect collector of Q1 to +12V through R3.
- One side of C1 goes to R3 and other side to R1.
- Emitter of Q1 go to GND.
- Base of Q1 connect to one pin of VR1 and other pin of VR1 to +12V.
- Connect collector of Q2 to +12V through R2.
- C2 one end goes to base of Q1 and VR1 and other end goes between R2 and collector of Q2.
- Emitter of Q2 to GND.
- Base of Q3 TIP122 connect between collector of Q2 and one end of C2.
- Emitter of Q3 to GND.
- Collector of Q3 go to +12V through R4 and LED1.
- Connect L1, L2, L3 coils 10W from +12V to GND.
- Use S1 between L1 and L2 and S2 between L2 and L3.
Conclusion:
This Transistor Based Battery Heater Circuit uses 12V power.
Made with astable multivibrator and TIP122 transistor it is easy to make and works well.
We can pick heating coils as we need with more or less heat.
Important to note that we should let heat go out safely and follow safety steps.