Patch three-end regulator block identification method:
1. Measure the inter-electrode resistance, place the multimeter in R×100 or R×1K gear, and test according to the different connections of the red and black watch pen. The forward resistance of the emitter junction and the collector junction is relatively low, and the interelectrode resistance of the silicon triode is larger than that of the germanium triode.
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2. The penetration current ICEO of the patch triode is equal to the product of the multiple β of the tube and the reverse current ICBO of the collector junction. ICBO grows rapidly with the increase of ambient temperature, and the tube with small ICEO should be preferred in use.
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3. The size of ICEO can be estimated by measuring the resistance between the e-c poles of the triode with a multimeter resistance
The three-terminal regulator is generally identified as LM 38 series or LM 39 series, the 38 series input is a positive voltage column, the 39 series input is a negative voltage, such as LM 3805, he is a positive voltage, positive five volts, LM 3905, it output is negative five volts