The TIP42 is a PNP transistor used in audio amplifier circuits and switching circuits. The transistor is very popular and easily available in any electronic components shops. This transistor is one of the best choices for the amplifier driver stage circuit. This is because of its high voltage of up to 100V and medium current of up to 6A carrying capacity. So In this article I’m sharing the pinout, characteristics and equivalent transistor of TIP42.
TIP42 Pinout
The TIP42 transistor is available in the TO-220 packaging. This type of package supports large aluminum mounting area and is very useful for the heat management while working the transistor continuously in a circuit. The pinout configuration of this transistor is given below,
- Pin 1 – Base
- Pin 2 – Collector
- Pin 3 – Emitter
Characteristics
| Parameter | Value |
| Type | PNP |
| Maximum Collector Current (Ic) | -6 A |
| Collector-Emitter Voltage (Vce) | -100 V (TIP42C) |
| Collector-Base Voltage (Vcb) | -100 V (TIP42C) |
| Emitter-Base Voltage (Veb) | -5 V |
| DC Current Gain (hFE) | 15 to 75 |
| Total Power Dissipation | 65 W |
| Package | TO-220 |
| Operating Temperature | -65 to +150 °C |
Transistor Variants
- TIP42A: Vce = – 60V
- TIP42B: Vce = – 80V
- TIP42C: Vce = – 100V
Applications
- Audio amplifier circuits
- Motor drivers
- Switching regulators
- Power supply circuits
- Inverter circuits
TIP42 Equivalent Transistors
If TIP42 PNP transistors are not available or difficult to get from your local market, you can use the following transistors as equivalents. Please note that Always check the specs and pinout of the transistors before replacing.
| Equivalent Transistor | Type | Notes |
| BD912 | PNP | Similar voltage and current rating |
| 2N5401 | PNP | For lower current applications |
| TIP32C | PNP | Slightly lower current rating |
| MJ2955 | PNP | Higher power PNP alternative |
| TIP147 | PNP Darlington | Higher gain, different characteristics |
How to Test TIP42
To check if a TIP42 is working or not using a multimeter.If the results are opposite or there’s no reading means that the transistor may be faulty. follow the given steps to identify the transistor is good or faulty,,
- Set the meter to diode mode.
- Place the positive lead on the base and the negative on the emitter or collector.
- You should get a reading (~0.6V) for both emitter and collector.
- Reversing the leads should show no conduction.
Conclusion
The TIP42 transistor is a useful PNP transistor in audio amplifier circuits and switching circuits. Before working with the TIP 42 circuits the given information about pinout, characteristics and equivalent transistors are important to know. The TIP41 is the complementary PNP transistor of TIP42.
