C1815 VS C945 – Difference and Comparison

In this article we are going to discuss about C1815 VS C945 transistor, their pinout difference, ratings and characteristics, interchangeability. Moreover we will also discuss in which condition you can and cannot interchange them.


C1815 VS C945



C1815 and C945 both are NPN transistors available in TO-92 and other packages. They are quite popular transistors and you can also find them in many commercial appliances and equipment. The main reasons for their popularity is their reliability, low price, easy availability and good specifications.


C1815 VS C945 Pin Difference

As seen in the pin comparison chart above the pin configuration of both the transistors are same. The first pin is Emitter, second is Collector and the third is Base.


Ratings & Characteristics Comparison:

Ratings & Characteristics C1815C945
Collector-Emitter Voltage (Vceo)50V50V
Collector Current (Ic)150mA150mA
Total Device Dissipation (PD)400mW 400mW
DC Current Gain (hFE)70 To 70070 To 700
Frequency (fT)80 MHz300 MHz


Can We Use C1815 Instead of C945

In the above ratings and characteristics chart we can see that both the transistor’s collector-emitter voltage is 50V, collector current is 150mA, total device dissipation is 400mW and the DC current gain is 70 to 700. The ratings of both transistors are almost same due to which you can use C1815 in the place of C945 in any switching and amplification applications except only in the RF applications that are working above 80MHz.


Can We Use C945 Instead of C1815

As mentioned above both the transistors have almost same ratings and characterstics, therefore, you can easily replace C945 with C1815 in all conditions such as switching, amplification, oscillation and other. Moreover, the C945 transition frequency is 300MHz due to which you can also use it instead of C1815 in RF circuits too.



Both the transistors are NPN type and TO-92 packages and both have almost the same ratings and characteristics so you easily use them in the place of each other in most of the applications. The only difference between the two is the transition frequency. The C1815 has a low transition frequency and the C945 has a higher transition frequency therefore only in RF circuits that are working above 80MHz you cannot use C1815 instead C945. So in this condition, you have to use an alternate transistor that has a higher or equal transition frequency to C945.




What is the use of C945 transistor?

C945 transistor is also designed to use in applicatiions such as audio frequency amplification and high frequency oscillation. But it is not limited to these uses and can also be used for a variety of other general purpose switching and amplification applications. Like its nearest equivalent C1815, it is also a good gain and low noise transistor.


Can I use 2N2222 instead of C945?

You can use 2N2222 instead of C945 in most of the conditions but 2N2222 is not a low noise transistor. So if you are using it in an audio preamplifier circuit or any circuit which requires a low noise transistor then you can use C945 nearest possible alternative C1815.

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